the required major version
the required minor version
the required micro version
NULL if the GTK+ library is compatible with the given version, or a string describing the version mismatch. The returned string is owned by GTK+ and should not be modified or freed.
Checks that the GTK+ library in use is compatible with the given version. Generally you would pass in the constants GTK_MAJOR_VERSION, GTK_MINOR_VERSION, GTK_MICRO_VERSION as the three arguments to this function; that produces a check that the library in use is compatible with the version of GTK+ the application or module was compiled against. Compatibility is defined by two things: first the version of the running library is newer than the version required_major.required_minor.required_micro. Second the running library must be binary compatible with the version required_major.required_minor.required_micro (same major version.) This function is primarily for GTK+ modules; the module can call this function to check that it wasn't loaded into an incompatible version of GTK+. However, such a check isn't completely reliable, since the module may be linked against an old version of GTK+ and calling the old version of gtk_check_version(), but still get loaded into an application using a newer version of GTK+.