XGetExtensionVersion - Man Page

#include <X11/extensions/XInput.h>

XExtensionVersion *XGetExtensionVersion( Display *display,
                                         char *name);

display
       Specifies the connection to the X server.

name
       Specifies the extension to be queried. The input
       extension name is defined in the header file XI.h.

The XGetExtensionVersion request is deprecated and should not
be used in XI2 applications. Clients issuing a XGetExtensionVersion
request will not be able to use XI2 features.

The XGetExtensionVersion request queries the version of the input
extension, and returns an XExtensionVersion structure. This structure
contains a major_version and minor_version number which can be compared
with constants defined in XI.h. Support for additional protocol
requests added to the input extension after its initial release
is indicated by a version number corresponding to the added
requests. Each version contains all the protocol requests
contained by previous versions.

You should use XFree to free the XExtensionVersion structure.

This request returns an XExtensionVersion structure.

typedef struct {
    int present;
    short major_version;
    short minor_version;
} XExtensionVersion;