3. Finding the X.Org X Server Version From a Client

The X.Org X servers report a VendorRelease value that matches the X.Org version number. There have been some cases of releases where this value wasn't set correctly. The rules for interpreting this value as well as the known exceptions are outlined here.

For post-6.7.0 development and release versions using the new numbering scheme, the VendorRelease value is MMmmPPsss. That is, version M.m.P.s has VendorRelease set to M * 10000000 + m * 100000 + P * 1000 + s.

The following is a code fragment taken from xdpyinfo.c that shows how the VendorRelease information can be interpreted.

    if (strstr(ServerVendor(dpy), "X.Org")) {
        int vendrel = VendorRelease(dpy);

        printf("X.Org version: ");
	printf("%d.%d.%d", vendrel / 10000000,
	       (vendrel /   100000) % 100,
	       (vendrel /     1000) % 100);
	if (vendrel % 1000) {
	    printf(".%d", vendrel % 1000);
	}
    }