## Version Information Version Information — Variables and functions to check the GLib version |

## Synopsis

    #include <glib.h>

    extern              const guint glib_major_version;
    extern              const guint glib_minor_version;
    extern              const guint glib_micro_version;
    extern              const guint glib_binary_age;
    extern              const guint glib_interface_age;
    const gchar*        glib_check_version                  (guint required_major,
                                                             guint required_minor,
                                                             guint required_micro);

    #define             GLIB_CHECK_VERSION                  (major,minor,micro)

## Description

GLib provides version information, primarily useful in configure checks for builds that have a configure script. Applications will not typically use the features described here.

## Details

### glib_major_version

    extern const guint glib_major_version;

The major version number of the GLib library. (e.g. in GLib version 1.2.5 this is 1.)

This variable is in the library, so represents the GLib library you have linked against. Contrast with the GLIB_MAJOR_VERSION macro, which represents the major version of the GLib headers you have included.

### glib_minor_version

    extern const guint glib_minor_version;

The minor version number of the GLib library. (e.g. in GLib version 1.2.5 this is 2.)

This variable is in the library, so represents the GLib library you have linked against. Contrast with the GLIB_MINOR_VERSION macro, which represents the minor version of the GLib headers you have included.

### glib_micro_version

    extern const guint glib_micro_version;

The micro version number of the GLib library. (e.g. in GLib version 1.2.5 this is 5.)

This variable is in the library, so represents the GLib library you have linked against. Contrast with the GLIB_MICRO_VERSION macro, which represents the micro version of the GLib headers you have included.

### glib_binary_age

    extern const guint glib_binary_age;

This is the binary age passed to libtool. If libtool means nothing to you, don't worry about it. ;-)

### glib_interface_age

    extern const guint glib_interface_age;

This is the interface age passed to libtool. If libtool means nothing to you, don't worry about it. ;-)

### glib_check_version ()

    const gchar*        glib_check_version                  (guint required_major,
                                                             guint required_minor,
                                                             guint required_micro);

Checks that the GLib library in use is compatible with the given version. Generally you would pass in the constants GLIB_MAJOR_VERSION, GLIB_MINOR_VERSION, GLIB_MICRO_VERSION as the three arguments to this function; that produces a check that the library in use is compatible with the version of GLib 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.)

`required_major` : | the required major version.
`required_minor` : | the required minor version.
`required_micro` : | the required micro version.
Returns : | `NULL` if the GLib library is compatible with the given version, or a string describing the version mismatch. The returned string is owned by GLib and must not be modified or freed.

Since 2.6

### GLIB_CHECK_VERSION()

    #define             GLIB_CHECK_VERSION(major,minor,micro)

Checks the version of the GLib library. Returns `TRUE` if the version of the GLib header files is the same as or newer than the passed-in version.

Example 1. Checking the version of the GLib library

      if (!GLIB_CHECK_VERSION (1, 2, 0))
        g_error ("GLib version 1.2.0 or above is needed");

`major` : | the major version number.
`minor` : | the minor version number.
`micro` : | the micro version number.