Asynchronous File Operations
3
GNOME-VFS-2.0 Library

# Asynchronous File Operations

POSIX-style file operations that run outside your main loop

## Synopsis

    #define             GNOME_VFS_PRIORITY_MIN
    #define             GNOME_VFS_PRIORITY_MAX
    #define             GNOME_VFS_PRIORITY_DEFAULT
    typedef             GnomeVFSAsyncHandle;
    void                (*GnomeVFSAsyncCallback)            (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncOpenCallback)        (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncOpenAsChannelCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GIOChannel *channel,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncCreateCallback)      (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncCreateAsChannelCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GIOChannel *channel,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncCloseCallback)       (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncReadCallback)        (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer buffer,
                                                             GnomeVFSFileSize bytes_requested,
                                                             GnomeVFSFileSize bytes_read,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncWriteCallback)       (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gconstpointer buffer,
                                                             GnomeVFSFileSize bytes_requested,
                                                             GnomeVFSFileSize bytes_written,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncSeekCallback)        (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncGetFileInfoCallback) (GnomeVFSAsyncHandle *handle,
                                                             GList *results,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncSetFileInfoCallback) (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             GnomeVFSFileInfo *file_info,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncFileControlCallback) (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer operation_data,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncDirectoryLoadCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             GList *list,
                                                             guint entries_read,
                                                             gpointer callback_data);
    void                (*GnomeVFSAsyncFindDirectoryCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GList *results,
                                                             gpointer data);
                        GnomeVFSFindDirectoryResult;
    gint                (*GnomeVFSAsyncXferProgressCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSXferProgressInfo *info,
                                                             gpointer user_data);
    typedef             GnomeVFSCancellation;
    typedef             GnomeVFSContext;
    void                gnome_vfs_async_set_job_limit       (int limit);
    int                 gnome_vfs_async_get_job_limit       (void);
    void                gnome_vfs_async_cancel              (GnomeVFSAsyncHandle *handle);
    void                gnome_vfs_async_open                (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_open_uri            (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_open_as_channel     (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             guint advised_block_size,
                                                             int priority,
                                                             GnomeVFSAsyncOpenAsChannelCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_open_uri_as_channel (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             guint advised_block_size,
                                                             int priority,
                                                             GnomeVFSAsyncOpenAsChannelCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_create              (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_create_uri          (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_create_symbolic_link
                                                            (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             const gchar *uri_reference,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_create_as_channel   (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncCreateAsChannelCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_create_uri_as_channel
                                                            (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncCreateAsChannelCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_close               (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSAsyncCloseCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_read                (GnomeVFSAsyncHandle *handle,
                                                             gpointer buffer,
                                                             guint bytes,
                                                             GnomeVFSAsyncReadCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_write               (GnomeVFSAsyncHandle *handle,
                                                             gconstpointer buffer,
                                                             guint bytes,
                                                             GnomeVFSAsyncWriteCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_seek                (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSSeekPosition whence,
                                                             GnomeVFSFileOffset offset,
                                                             GnomeVFSAsyncSeekCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_get_file_info       (GnomeVFSAsyncHandle **handle_return,
                                                             GList *uri_list,
                                                             GnomeVFSFileInfoOptions options,
                                                             int priority,
                                                             GnomeVFSAsyncGetFileInfoCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_set_file_info       (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSFileInfo *info,
                                                             GnomeVFSSetFileInfoMask mask,
                                                             GnomeVFSFileInfoOptions options,
                                                             int priority,
                                                             GnomeVFSAsyncSetFileInfoCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_load_directory      (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSFileInfoOptions options,
                                                             guint items_per_notification,
                                                             int priority,
                                                             GnomeVFSAsyncDirectoryLoadCallback callback,
                                                             gpointer callback_data);
    void                gnome_vfs_async_load_directory_uri  (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSFileInfoOptions options,
                                                             guint items_per_notification,
                                                             int priority,
                                                             GnomeVFSAsyncDirectoryLoadCallback callback,
                                                             gpointer callback_data);
    GnomeVFSResult      gnome_vfs_async_xfer                (GnomeVFSAsyncHandle **handle_return,
                                                             GList *source_uri_list,
                                                             GList *target_uri_list,
                                                             GnomeVFSXferOptions xfer_options,
                                                             GnomeVFSXferErrorMode error_mode,
                                                             GnomeVFSXferOverwriteMode overwrite_mode,
                                                             int priority,
                                                             GnomeVFSAsyncXferProgressCallback progress_update_callback,
                                                             gpointer update_callback_data,
                                                             GnomeVFSXferProgressCallback progress_sync_callback,
                                                             gpointer sync_callback_data);
    void                gnome_vfs_async_find_directory      (GnomeVFSAsyncHandle **handle_return,
                                                             GList *near_uri_list,
                                                             GnomeVFSFindDirectoryKind kind,
                                                             gboolean create_if_needed,
                                                             gboolean find_if_needed,
                                                             guint permissions,
                                                             int priority,
                                                             GnomeVFSAsyncFindDirectoryCallback callback,
                                                             gpointer user_data);
    void                gnome_vfs_async_file_control        (GnomeVFSAsyncHandle *handle,
                                                             const char *operation,
                                                             gpointer operation_data,
                                                             GDestroyNotify operation_data_destroy_func,
                                                             GnomeVFSAsyncFileControlCallback callback,
                                                             gpointer callback_data);
    GnomeVFSFindDirectoryResult* gnome_vfs_find_directory_result_dup
                                                            (GnomeVFSFindDirectoryResult *result);
    void                gnome_vfs_find_directory_result_free
                                                            (GnomeVFSFindDirectoryResult *result);

## Description

When executing an asynchornous operation on a file the program does not block waiting for the operation to finish, instead it keeps on running, which means that the process and the I/O operation can be both running concurrently. Once the I/O operation has been completed the process is notified using a callback.

Asynchronous operations are particularly good when long I/O operations are expected, in this case the program can continue normaly, the I/O will be performed in the background. On the other hand when operations are expected to be short (creating a file, writing/reading small amounts of data, etc.) synchronous operations are prefered.

Within a graphical desktop asynchornous I/O operations can be used to avoid blocking the UI (User Interface) during a long operation, and to be able to provide some kind of feedback to the user.

## Details

### GNOME_VFS_PRIORITY_MIN

    #define GNOME_VFS_PRIORITY_MIN     -10

The minimuum priority a job can have.

### GNOME_VFS_PRIORITY_MAX

    #define GNOME_VFS_PRIORITY_MAX     10

The maximuum priority a job can have.

### GNOME_VFS_PRIORITY_DEFAULT

    #define GNOME_VFS_PRIORITY_DEFAULT 0

The default job priority. Its best to use this unless you have a reason to do otherwise.

### GnomeVFSAsyncHandle

    typedef struct GnomeVFSAsyncHandle GnomeVFSAsyncHandle;

### GnomeVFSAsyncCallback ()

    void                (*GnomeVFSAsyncCallback)            (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

Basic callback from an async operation that passes no data back, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established

### GnomeVFSAsyncOpenCallback ()

    void                (*GnomeVFSAsyncOpenCallback)        (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_open()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established

### GnomeVFSAsyncOpenAsChannelCallback ()

    void                (*GnomeVFSAsyncOpenAsChannelCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GIOChannel *channel,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

`GnomeVFSAsyncOpenAsChannelCallback` is deprecated and should not be used in newly-written code.

Callback for the `gnome_vfs_async_open_as_channel()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback.

`channel` :

  a GIOChannel corresponding to the file opened

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established.

### GnomeVFSAsyncCreateCallback ()

    void                (*GnomeVFSAsyncCreateCallback)      (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_create()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established

### GnomeVFSAsyncCreateAsChannelCallback ()

    void                (*GnomeVFSAsyncCreateAsChannelCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GIOChannel *channel,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

`GnomeVFSAsyncCreateAsChannelCallback` is deprecated and should not be used in newly-written code.

Callback for the `gnome_vfs_async_create_as_channel()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback.

`channel` :

  a GIOChannel corresponding to the file created

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established.

### GnomeVFSAsyncCloseCallback ()

    void                (*GnomeVFSAsyncCloseCallback)       (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_close()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established

### GnomeVFSAsyncReadCallback ()

    void                (*GnomeVFSAsyncReadCallback)        (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer buffer,
                                                             GnomeVFSFileSize bytes_requested,
                                                             GnomeVFSFileSize bytes_read,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_read()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`buffer` :

  buffer containing data read from `handle`.

`bytes_requested` :

  the number of bytes asked for in the call to `gnome_vfs_async_read()`.

`bytes_read` :

  the number of bytes actually read from `handle` into `buffer`.

`callback_data` :

  user data defined when the callback was established

### GnomeVFSAsyncWriteCallback ()

    void                (*GnomeVFSAsyncWriteCallback)       (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gconstpointer buffer,
                                                             GnomeVFSFileSize bytes_requested,
                                                             GnomeVFSFileSize bytes_written,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_write()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`buffer` :

  buffer containing data written to `handle`.

`bytes_requested` :

  the number of bytes asked to write in the call to `gnome_vfs_async_write()`.

`bytes_written` :

  the number of bytes actually written to `handle` from `buffer`.

`callback_data` :

  user data defined when the callback was established.

### GnomeVFSAsyncSeekCallback ()

    void                (*GnomeVFSAsyncSeekCallback)        (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_seek()` function, informing the user of the `result` of the operation.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise an error code.

`callback_data` :

  user data defined when the callback was established.

### GnomeVFSAsyncGetFileInfoCallback ()

    void                (*GnomeVFSAsyncGetFileInfoCallback) (GnomeVFSAsyncHandle *handle,
                                                             GList *results,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_get_file_info()` function, informing the user of the `results` of the operation.

`handle` :

  handle of the operation generating the callback

`results` :

  GList of GnomeVFSFileInfoResult * items representing the success of each `gnome_vfs_get_file_info()` and the data retrieved.

`callback_data` :

  user data defined when the callback was established.

### GnomeVFSAsyncSetFileInfoCallback ()

    void                (*GnomeVFSAsyncSetFileInfoCallback) (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             GnomeVFSFileInfo *file_info,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_set_file_info()` function, informing the user of the `result` of the operation and returning the new `file_info`.

Setting the file info sometimes changes more information than the caller specified; for example, if the name changes the MIME type might change, and if the owner changes the SUID & SGID bits might change. Therefore the callback returns the new `file_info` for the caller's convenience. The GnomeVFSFileInfoOptions passed here are those used for the returned file info; they are not used when setting.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise a GnomeVFSResult error code.

`file_info` :

  if `result` is `GNOME_VFS_OK`, a GnomeVFSFileInfo struct containing information about the file.

`callback_data` :

  user data defined when the callback was established

### GnomeVFSAsyncFileControlCallback ()

    void                (*GnomeVFSAsyncFileControlCallback) (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             gpointer operation_data,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_find_directory()` function. informing the user of the `result` of the operation, and providing the requested `operation_data`.

`handle` :

  handle of the operation generating the callback

`result` :

  `GNOME_VFS_OK` if the operation was successful, otherwise a GnomeVFSResult error code.

`operation_data` :

  The data requested from the module if `result` is `GNOME_VFS_OK`.

`callback_data` :

  User data defined when the operation was established.

### GnomeVFSAsyncDirectoryLoadCallback ()

    void                (*GnomeVFSAsyncDirectoryLoadCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSResult result,
                                                             GList *list,
                                                             guint entries_read,
                                                             gpointer callback_data);

Callback for the `gnome_vfs_async_directory_load()` function. informing the user of the `result` of the operation and providing a file `list` if the `result` is `GNOME_VFS_OK`.

`handle` :

  handle of the operation generating the callback.

`result` :

  `GNOME_VFS_OK` if the operation was sucessful, `GNOME_VFS_ERROR_EOF` if the last file in the directory has been read, otherwise a GnomeVFSResult error code

`list` :

  a GList of GnomeVFSFileInfo structs representing information about the files just loaded.

`entries_read` :

  number of entries read from `handle` for this instance of the callback.

`callback_data` :

  user data defined when the callback was established.

### GnomeVFSAsyncFindDirectoryCallback ()

    void                (*GnomeVFSAsyncFindDirectoryCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GList *results,
                                                             gpointer data);

Callback for the `gnome_vfs_async_find_directory()` function, informing the user of the `results` of the operation.

`handle` :

  handle of the operation generating the callback

`results` :

  GList of GnomeVFSFindDirectoryResult *s containing special directories matching the find criteria.

`data` :

  user data defined when the operation was established

### GnomeVFSFindDirectoryResult

    typedef struct {
    	GnomeVFSURI *uri;
    	GnomeVFSResult result;
    } GnomeVFSFindDirectoryResult;

This structure is passed to a GnomeVFSAsyncFindDirectoryCallback by `gnome_vfs_async_find_directory()` and contains the information associated with a single GnomeVFSURI matching the specified find request.

GnomeVFSURI *uri;

  The GnomeVFSURI that was found.

GnomeVFSResult result;

  The GnomeVFSResult that was obtained when finding `uri`.

### GnomeVFSAsyncXferProgressCallback ()

    gint                (*GnomeVFSAsyncXferProgressCallback)
                                                            (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSXferProgressInfo *info,
                                                             gpointer user_data);

This callback is passed to `gnome_vfs_async_xfer()` and should be used for user interaction. That said, it serves two purposes: Informing the user about the progress of the operation, and making decisions.

On the one hand, when the transfer progresses normally, i.e. when the `info`'s status is `GNOME_VFS_XFER_PROGRESS_STATUS_OK` it is called periodically whenever new progress information is available, and it wasn't called already within the last 100 milliseconds.

On the other hand, it is called whenever a decision is requested from the user, i.e. whenever the `info`'s `status` is not `GNOME_VFS_XFER_PROGRESS_STATUS_OK`.

Either way, it acts like GnomeVFSXferProgressCallback would act in non-asynchronous mode. The differences in invocation are explained in the `gnome_vfs_async_xfer()` documentation.

`handle` :

  Handle of the Xfer operation generating the callback.

`info` :

  Information on the current progress in the transfer.

`user_data` :

  The user data that was passed to `gnome_vfs_async_xfer()`.

Returns :

  `gint` depending on the GnomeVFSXferProgressInfo. Please consult GnomeVFSXferProgressCallback for details.

### GnomeVFSCancellation

    typedef struct GnomeVFSCancellation GnomeVFSCancellation;

### GnomeVFSContext

    typedef struct GnomeVFSContext GnomeVFSContext;

### gnome_vfs_async_set_job_limit ()

    void                gnome_vfs_async_set_job_limit       (int limit);

Restrict the number of worker threads used by async operations to `limit`.

`limit` :

  maximum number of allowable threads.

### gnome_vfs_async_get_job_limit ()

    int                 gnome_vfs_async_get_job_limit       (void);

Get the current maximum allowable number of worker threads for async operations.

Returns :

  current maximum number of threads.

### gnome_vfs_async_cancel ()

    void                gnome_vfs_async_cancel              (GnomeVFSAsyncHandle *handle);

Cancel an asynchronous operation and close all its callbacks.

In a single-threaded application, its guaranteed that if you call this before the operation finished callback has been called the callback will never be called.

However, in a multithreaded application, or to be more specific, if you call gnome_vfs_async_cancel from another thread than the thread handling the glib mainloop, there is a race condition where if the operation finished callback was just dispatched, you might still cancel the operation. So, in this case you need to handle the fact that the operation callback might still run even though another thread has cancelled the operation.

One way to avoid problems from this is to mark the data structure you're using as callback_data as destroyed, and then queue an idle and do the actual freeing in an idle handler. The idle handler is guaranteed to run after the callback has been exectuted, so by then it is safe to destroy the callback_data. The callback handler must handle the case where the callback_data is marked destroyed by doing nothing.

This is clearly not ideal for multithreaded applications, but as good as we can with the current API. Eventually we'll have to change the API to make this work better.

`handle` :

  handle of the async operation to be cancelled.

### gnome_vfs_async_open ()

    void                gnome_vfs_async_open                (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);

Open `text_uri` according to mode `open_mode`. On return, `handle_return` will contain a pointer to the operation. Once the file has been successfully opened, `callback` will be called with the GnomeVFSResult.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`text_uri` :

  string of the uri to open.

`open_mode` :

  open mode.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign to this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_open_uri ()

    void                gnome_vfs_async_open_uri            (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);

Open `uri` according to mode `open_mode`. On return, `handle_return` will contain a pointer to the operation. Once the file has been successfully opened, `callback` will be called with the GnomeVFSResult.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`uri` :

  uri to open.

`open_mode` :

  open mode.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign to this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_open_as_channel ()

    void                gnome_vfs_async_open_as_channel     (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             guint advised_block_size,
                                                             int priority,
                                                             GnomeVFSAsyncOpenAsChannelCallback callback,
                                                             gpointer callback_data);

`gnome_vfs_async_open_as_channel` is deprecated and should not be used in newly-written code.

Open `text_uri` as a GIOChannel. Once the channel has been established `callback` will be called with `callback_data`, the result of the operation, and if the result was `GNOME_VFS_OK`, a reference to a GIOChannel pointing at `text_uri` in `open_mode`.

This function has been deprecated due to behaving weirdly which suggests that it hasn't been used. See bugs 157266, 157265, 157261, 138398 in the GNOME Bugzilla. If the *_as_channel functions are needed they should be fixed and undeprecated.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`text_uri` :

  string of the uri to open as a GIOChannel.

`open_mode` :

  open mode i.e. for reading, writing, random, etc.

`advised_block_size` :

  the preferred block size for GIOChannel to read.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_open_uri_as_channel ()

    void                gnome_vfs_async_open_uri_as_channel (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             guint advised_block_size,
                                                             int priority,
                                                             GnomeVFSAsyncOpenAsChannelCallback callback,
                                                             gpointer callback_data);

`gnome_vfs_async_open_uri_as_channel` is deprecated and should not be used in newly-written code. This function has been deprecated due to behaving weirdly which suggests that it shouldn't be used. See bugs 157266, 157265, 157261, 138398 in the GNOME Bugzilla. If the *_as_channel functions are needed they should be fixed and undeprecated.

Open `uri` as a GIOChannel. Once the channel has been established `callback` will be called with `callback_data`, the result of the operation, and if the result was `GNOME_VFS_OK`, a reference to a GIOChannel pointing at `uri` in `open_mode`.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`uri` :

  uri to open as a GIOChannel.

`open_mode` :

  open mode i.e. for reading, writing, random, etc.

`advised_block_size` :

  the preferred block size for GIOChannel to read.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_create ()

    void                gnome_vfs_async_create              (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);

Create a file at `uri` according to mode `open_mode`, with permissions `perm` (in the standard UNIX packed bit permissions format). When the create has been completed `callback` will be called with the result code and `callback_data`.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`text_uri` :

  string representing the uri to create.

`open_mode` :

  mode to leave the file opened in after creation (or `GNOME_VFS_OPEN_MODE_NONE` to leave the file closed after creation).

`exclusive` :

  whether the file should be created in "exclusive" mode: i.e. if this flag is nonzero, operation will fail if a file with the same name already exists.

`perm` :

  bitmap representing the permissions for the newly created file (Unix style).

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_create_uri ()

    void                gnome_vfs_async_create_uri          (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);

Create a file at `uri` according to mode `open_mode`, with permissions `perm` (in the standard UNIX packed bit permissions format). When the create has been completed `callback` will be called with the result code and `callback_data`.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`uri` :

  uri to create a file at.

`open_mode` :

  mode to leave the file opened in after creation (or `GNOME_VFS_OPEN_MODE_NONE` to leave the file closed after creation).

`exclusive` :

  Whether the file should be created in "exclusive" mode: i.e. if this flag is nonzero, operation will fail if a file with the same name already exists.

`perm` :

  bitmap representing the permissions for the newly created file (Unix style).

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_create_symbolic_link ()

    void                gnome_vfs_async_create_symbolic_link
                                                            (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             const gchar *uri_reference,
                                                             int priority,
                                                             GnomeVFSAsyncOpenCallback callback,
                                                             gpointer callback_data);

Create a symbolic link at `uri` pointing to `uri_reference`. When the operation has completed `callback` will be called with the result of the operation and `callback_data`.

`handle_return` :

  when the function returns, will point to a handle for the async operation.

`uri` :

  location to create the link at.

`uri_reference` :

  location to point `uri` to (can be a uri fragment, i.e. relative).

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign to this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_create_as_channel ()

    void                gnome_vfs_async_create_as_channel   (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncCreateAsChannelCallback callback,
                                                             gpointer callback_data);

`gnome_vfs_async_create_as_channel` is deprecated and should not be used in newly-written code.

Open `text_uri` as a GIOChannel, creating it as necessary. Once the channel has been established `callback` will be called with `callback_data`, the result of the operation, and if the result was `GNOME_VFS_OK`, a reference to a GIOChannel pointing at `text_uri` in `open_mode`.

This function has been deprecated due to behaving weirdly which suggests that it hasn't been used. See bugs 157266, 157265, 157261, 138398 in the GNOME Bugzilla. If the *_as_channel functions are needed they should be fixed and undeprecated.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`text_uri` :

  string of the uri to open as a GIOChannel, creating it as necessary.

`open_mode` :

  open mode i.e. for reading, writing, random, etc.

`exclusive` :

  replace the file if it already exists.

`perm` :

  standard POSIX-style permissions bitmask, permissions of created file.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_create_uri_as_channel ()

    void                gnome_vfs_async_create_uri_as_channel
                                                            (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSOpenMode open_mode,
                                                             gboolean exclusive,
                                                             guint perm,
                                                             int priority,
                                                             GnomeVFSAsyncCreateAsChannelCallback callback,
                                                             gpointer callback_data);

`gnome_vfs_async_create_uri_as_channel` is deprecated and should not be used in newly-written code.

Open `uri` as a GIOChannel, creating it as necessary. Once the channel has been established `callback` will be called with `callback_data`, the result of the operation, and if the result was `GNOME_VFS_OK`, a reference to a GIOChannel pointing at `text_uri` in `open_mode`.

`handle_return` :

  pointer to a pointer to a GnomeVFSHandle object.

`uri` :

  uri to open as a GIOChannel, creating it as necessary.

`open_mode` :

  open mode i.e. for reading, writing, random, etc.

`exclusive` :

  replace the file if it already exists.

`perm` :

  standard POSIX-style permissions bitmask, permissions of created file.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

Since 2.12

### gnome_vfs_async_close ()

    void                gnome_vfs_async_close               (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSAsyncCloseCallback callback,
                                                             gpointer callback_data);

Close `handle` opened with `gnome_vfs_async_open()`. When the close has completed, `callback` will be called with `callback_data` and the result of the operation.

`handle` :

  async handle to close.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_read ()

    void                gnome_vfs_async_read                (GnomeVFSAsyncHandle *handle,
                                                             gpointer buffer,
                                                             guint bytes,
                                                             GnomeVFSAsyncReadCallback callback,
                                                             gpointer callback_data);

Read `bytes` bytes from the file pointed to be `handle` into `buffer`. When the operation is complete, `callback` will be called with the result of the operation and `callback_data`.

`handle` :

  handle for the file to be read.

`buffer` :

  allocated block of memory to read into.

`bytes` :

  number of bytes to read.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_write ()

    void                gnome_vfs_async_write               (GnomeVFSAsyncHandle *handle,
                                                             gconstpointer buffer,
                                                             guint bytes,
                                                             GnomeVFSAsyncWriteCallback callback,
                                                             gpointer callback_data);

Write `bytes` bytes from `buffer` into the file pointed to be `handle`. When the operation is complete, `callback` will be called with the result of the operation and `callback_data`.

`handle` :

  handle for the file to be written.

`buffer` :

  block of memory containing data to be written.

`bytes` :

  number of bytes to write.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_seek ()

    void                gnome_vfs_async_seek                (GnomeVFSAsyncHandle *handle,
                                                             GnomeVFSSeekPosition whence,
                                                             GnomeVFSFileOffset offset,
                                                             GnomeVFSAsyncSeekCallback callback,
                                                             gpointer callback_data);

Set the current position for reading/writing through `handle`. When the operation is complete, `callback` will be called with the result of the operation and `callback_data`.

`handle` :

  handle for which the current position must be changed.

`whence` :

  integer value representing the starting position.

`offset` :

  number of bytes to skip from the position specified by `whence`. (a positive value means to move forward; a negative one to move backwards).

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_get_file_info ()

    void                gnome_vfs_async_get_file_info       (GnomeVFSAsyncHandle **handle_return,
                                                             GList *uri_list,
                                                             GnomeVFSFileInfoOptions options,
                                                             int priority,
                                                             GnomeVFSAsyncGetFileInfoCallback callback,
                                                             gpointer callback_data);

Fetch information about the files indicated in `uri_list` and return the information progressively to `callback`.

`handle_return` :

  when the function returns, will point to a handle for the async operation.

`uri_list` :

  a GList of GnomeVFSURIs to fetch information about.

`options` :

  packed boolean type providing control over various details of the get_file_info operation.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_set_file_info ()

    void                gnome_vfs_async_set_file_info       (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSFileInfo *info,
                                                             GnomeVFSSetFileInfoMask mask,
                                                             GnomeVFSFileInfoOptions options,
                                                             int priority,
                                                             GnomeVFSAsyncSetFileInfoCallback callback,
                                                             gpointer callback_data);

Set file info details about the file at `uri`, such as permissions, name, owner, and modification time.

`handle_return` :

  when the function returns, will point to a handle for the async operation.

`uri` :

  uri to set the file info of.

`info` :

  the struct containing new information about the file.

`mask` :

  control which fields of `info` are to be changed about the file at `uri`.

`options` :

  packed boolean type providing control over various details of the set_file_info operation.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_load_directory ()

    void                gnome_vfs_async_load_directory      (GnomeVFSAsyncHandle **handle_return,
                                                             const gchar *text_uri,
                                                             GnomeVFSFileInfoOptions options,
                                                             guint items_per_notification,
                                                             int priority,
                                                             GnomeVFSAsyncDirectoryLoadCallback callback,
                                                             gpointer callback_data);

Read the contents of the directory at `text_uri`, passing back GnomeVFSFileInfo structs about each file in the directory to `callback`. `items_per_notification` files will be processed between each call to `callback`.

`handle_return` :

  when the function returns, will point to a handle for the async operation.

`text_uri` :

  string representing the uri of the directory to be loaded.

`options` :

  packed boolean type providing control over various details of the get_file_info operation.

`items_per_notification` :

  number of files to process in a row before calling `callback`

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign to this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_load_directory_uri ()

    void                gnome_vfs_async_load_directory_uri  (GnomeVFSAsyncHandle **handle_return,
                                                             GnomeVFSURI *uri,
                                                             GnomeVFSFileInfoOptions options,
                                                             guint items_per_notification,
                                                             int priority,
                                                             GnomeVFSAsyncDirectoryLoadCallback callback,
                                                             gpointer callback_data);

Read the contents of the directory at `uri`, passing back GnomeVFSFileInfo structs about each file in the directory to `callback`. `items_per_notification` files will be processed between each call to `callback`.

`handle_return` :

  when the function returns, will point to a handle for the async operation.

`uri` :

  uri of the directory to be loaded.

`options` :

  packed boolean type providing control over various details of the get_file_info operation.

`items_per_notification` :

  number of files to process in a row before calling `callback`

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`callback_data` :

  data to pass to `callback`.

### gnome_vfs_async_xfer ()

    GnomeVFSResult      gnome_vfs_async_xfer                (GnomeVFSAsyncHandle **handle_return,
                                                             GList *source_uri_list,
                                                             GList *target_uri_list,
                                                             GnomeVFSXferOptions xfer_options,
                                                             GnomeVFSXferErrorMode error_mode,
                                                             GnomeVFSXferOverwriteMode overwrite_mode,
                                                             int priority,
                                                             GnomeVFSAsyncXferProgressCallback progress_update_callback,
                                                             gpointer update_callback_data,
                                                             GnomeVFSXferProgressCallback progress_sync_callback,
                                                             gpointer sync_callback_data);

Performs an Xfer operation in a seperate thread, otherwise like `gnome_vfs_xfer_uri_list()`.

See GnomeVFSAsyncXferProgressCallback and GnomeVFSXferProgressCallback for details on how the callback mechanism works.

`progress_sync_callback` should only be used if you want to execute additional actions that may not wait until after the transfer, for instance because you have to do them for each transferred file/directory, and that require a very specific action to be taken. For instance, the Nautilus application schedules metadata removal/moving/copying at specific phases.

Do not use `progress_sync_callback` if you just need user feedback, because each invocation is expensive, and requires a context switch.

If you use both `progress_update_callback` and `progress_sync_callback`, the `progress_sync_callback` will always be invoked before the `progress_update_callback`. It is recommended to do conflict handling in `progress_update_callback`, and always return `TRUE` in `progress_sync_callback`, because if the Xfer's GnomeVFSXferProgressStatus is `GNOME_VFS_XFER_PROGRESS_STATUS_OK`, `progress_update_callback` will only be invoked if it hasn't been invoked within the last 100 milliseconds, and if `progress_update_callback` is not invoked, only `progress_sync_callback` is authoritative for the further processing, causing abortion if it is `FALSE`.

`handle_return` :

  when the function returns, will point to a handle for the operation.

`source_uri_list` :

  A GList of source GnomeVFSURIs.

`target_uri_list` :

  A GList of target GnomeVFSURIs, each corresponding to one URI in `source_uri_list`.

`xfer_options` :

  GnomeVFSXferOptions defining the desired operation and parameters.

`error_mode` :

  A GnomeVFSErrorMode specifying how to proceed if a VFS error occurs.

`overwrite_mode` :

  A GnomeVFSOverwriteMode specifying how to proceed if a file is being overwritten.

`priority` :

  A value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign this job in allocating threads from the thread pool.

`progress_update_callback` :

  A GnomeVFSAsyncXferCallback called periodically for informing the program about progress, and when the program requires responses to interactive queries (e.g. overwriting files, handling errors, etc).

`update_callback_data` :

  User data to pass to `progress_update_callback`.

`progress_sync_callback` :

  An optional GnomeVFSXferCallback called whenever some state changed.

`sync_callback_data` :

  User data to pass to `progress_sync_callback`.

Returns :

  `GNOME_VFS_OK` if the paramaters were in order, or `GNOME_VFS_ERROR_BAD_PARAMETERS` if something was wrong in the passed in arguments.

### gnome_vfs_async_find_directory ()

    void                gnome_vfs_async_find_directory      (GnomeVFSAsyncHandle **handle_return,
                                                             GList *near_uri_list,
                                                             GnomeVFSFindDirectoryKind kind,
                                                             gboolean create_if_needed,
                                                             gboolean find_if_needed,
                                                             guint permissions,
                                                             int priority,
                                                             GnomeVFSAsyncFindDirectoryCallback callback,
                                                             gpointer user_data);

Used to return special directories such as Trash and Desktop from different file systems.

There is quite a complicated logic behind finding/creating a Trash directory and you need to be aware of some implications: Finding the Trash the first time when using the file method may be pretty expensive. A cache file is used to store the location of that Trash file for next time. If `create_if_needed` is specified without `find_if_needed`, you may end up creating a Trash file when there already is one. Your app should start out by doing a gnome_vfs_find_directory with the `find_if_needed` to avoid this and then use the `create_if_needed` flag to create Trash lazily when it is needed for throwing away an item on a given disk.

When the operation has completed, `callback` will be called with the result of the operation and `user_data`.

`handle_return` :

  when the function returns, will point to a handle for the operation.

`near_uri_list` :

  a GList of GnomeVFSURIs, find a special directory on the same volume as `near_uri_list`.

`kind` :

  kind of special directory.

`create_if_needed` :

  if directory we are looking for does not exist, try to create it.

`find_if_needed` :

  if we don't know where the directory is yet, look for it.

`permissions` :

  if creating, use these permissions.

`priority` :

  a value from `GNOME_VFS_PRIORITY_MIN` to `GNOME_VFS_PRIORITY_MAX` (normally should be `GNOME_VFS_PRIORITY_DEFAULT`) indicating the priority to assign to this job in allocating threads from the thread pool.

`callback` :

  function to be called when the operation is complete.

`user_data` :

  data to pass to `callback`.

### gnome_vfs_async_file_control ()

    void                gnome_vfs_async_file_control        (GnomeVFSAsyncHandle *handle,
                                                             const char *operation,
                                                             gpointer operation_data,
                                                             GDestroyNotify operation_data_destroy_func,
                                                             GnomeVFSAsyncFileControlCallback callback,
                                                             gpointer callback_data);

Execute a backend dependent operation specified by the string `operation`. This is typically used for specialized vfs backends that need additional operations that gnome-vfs doesn't have. Compare it to the unix call `ioctl()`. The format of `operation_data` depends on the operation. Operation that are backend specific are normally namespaced by their module name.

When the operation is complete, `callback` will be called with the result of the operation, `operation_data` and `callback_data`.

`handle` :

  handle of the file to affect.

`operation` :

  operation to execute.

`operation_data` :

  data needed to execute the operation.

`operation_data_destroy_func` :

  callback to destroy `operation_data` when its no longer needed.

`callback` :

  function to be called when the `operation` is complete.

`callback_data` :

  data to pass to `callback`.

Since 2.2

### gnome_vfs_find_directory_result_dup ()

    GnomeVFSFindDirectoryResult* gnome_vfs_find_directory_result_dup
                                                            (GnomeVFSFindDirectoryResult *result);

Duplicates `result`.

Note: The internal uri is not duplicated but its refcount is incremented.

`result` :

  a GnomeVFSFindDirectoryResult.

Returns :

  A 1:1 copy of `result`.

Since 2.12

### gnome_vfs_find_directory_result_free ()

    void                gnome_vfs_find_directory_result_free
                                                            (GnomeVFSFindDirectoryResult *result);

Unrefs the inner uri object and frees the memory allocated for `result`.

`result` :

  a GnomeVFSFindDirectoryResult.

Since 2.12