GLib Reference Manual
<<< Previous Page | Home | Up | Next Page >>>

# Basic Types

## Name

Basic Types -- standard GLib types, defined for ease-of-use and portability.

## Synopsis

    #include <glib.h>

    typedef     gboolean;
    typedef     gpointer;
    typedef     gconstpointer;
    typedef     gchar;
    typedef     guchar;

    typedef     gint;
    typedef     guint;
    typedef     gshort;
    typedef     gushort;
    typedef     glong;
    typedef     gulong;

    typedef     gint8;
    typedef     guint8;
    typedef     gint16;
    typedef     guint16;
    typedef     gint32;
    typedef     guint32;

    #define     G_HAVE_GINT64
    typedef     gint64;
    typedef     guint64;
    #define     G_GINT64_CONSTANT               (val)

    typedef     gfloat;
    typedef     gdouble;

    typedef     gsize;
    typedef     gssize;

## Description

GLib defines a number of commonly used types, which can be divided into 4 groups:

- New types which are not part of standard C - gboolean, gsize, gssize.

- Integer types which are guaranteed to be the same size across all platforms - gint8, guint8, gint16, guint16, gint32, guint32, gint64, guint64.

- Types which are easier to use than their standard C counterparts - gpointer, gconstpointer, guchar, guint, gushort, gulong.

- Types which correspond exactly to standard C types, but are included for completeness - gchar, gint, gshort, glong, gfloat, gdouble.

## Details

### gboolean

    typedef gint   gboolean;

A standard boolean type. Variables of this type should only contain the value TRUE or FALSE.

### gpointer

    typedef void* gpointer;

An untyped pointer. gpointer looks better and is easier to use than void*.

### gconstpointer

    typedef const void *gconstpointer;

An untyped pointer to constant data. The data pointed to should not be changed.

This is typically used in function prototypes to indicate that the data pointed to will not be altered by the function.

### gchar

    typedef char   gchar;

Corresponds to the standard C char type.

### guchar

    typedef unsigned char   guchar;

Corresponds to the standard C unsigned char type.

### gint

    typedef int    gint;

Corresponds to the standard C int type. Values of this type can range from G_MININT to G_MAXINT.

### guint

    typedef unsigned int    guint;

Corresponds to the standard C unsigned int type. Values of this type can range from 0 to G_MAXUINT.

### gshort

    typedef short  gshort;

Corresponds to the standard C short type. Values of this type can range from G_MINSHORT to G_MAXSHORT.

### gushort

    typedef unsigned short  gushort;

Corresponds to the standard C unsigned short type. Values of this type can range from 0 to G_MAXUSHORT.

### glong

    typedef long   glong;

Corresponds to the standard C long type. Values of this type can range from G_MINLONG to G_MAXLONG.

### gulong

    typedef unsigned long   gulong;

Corresponds to the standard C unsigned long type. Values of this type can range from 0 to G_MAXULONG.

### gint8

    typedef signed char gint8;

A signed integer guaranteed to be 8 bits on all platforms. Values of this type can range from -128 to 127.

### guint8

    typedef unsigned char guint8;

An unsigned integer guaranteed to be 8 bits on all platforms. Values of this type can range from 0 to 255.

### gint16

    typedef signed short gint16;

A signed integer guaranteed to be 16 bits on all platforms. Values of this type can range from -32,768 to 32,767.

### guint16

    typedef unsigned short guint16;

An unsigned integer guaranteed to be 16 bits on all platforms. Values of this type can range from 0 to 65,535.

### gint32

    typedef signed int gint32;

A signed integer guaranteed to be 32 bits on all platforms. Values of this type can range from -2,147,483,648 to 2,147,483,647.

### guint32

    typedef unsigned int guint32;

An unsigned integer guaranteed to be 32 bits on all platforms. Values of this type can range from 0 to 4,294,967,295.

### G_HAVE_GINT64

    #define G_HAVE_GINT64 1          /* deprecated, always true */

This macro is defined if 64-bit signed and unsigned integers are available on the platform.

### gint64

    G_GNUC_EXTENSION typedef signed long long gint64;

A signed integer guaranteed to be 64 bits on all platforms on which it is available (see G_HAVE_GINT64). Values of this type can range from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

### guint64

    G_GNUC_EXTENSION typedef unsigned long long guint64;

An unsigned integer guaranteed to be 64 bits on all platforms on which it is available (see G_HAVE_GINT64). Values of this type can range from 0 to 18,446,744,073,709,551,615.

### G_GINT64_CONSTANT()

    #define G_GINT64_CONSTANT(val)	(G_GNUC_EXTENSION (val##LL))

This macro is used to insert 64-bit integer literals into the source code.

`val` : | a literal integer value, e.g. 0x1d636b02300a7aa7U.

### gfloat

    typedef float   gfloat;

Corresponds to the standard C float type. Values of this type can range from G_MINFLOAT to G_MAXFLOAT.

### gdouble

    typedef double  gdouble;

Corresponds to the standard C double type. Values of this type can range from G_MINDOUBLE to G_MAXDOUBLE.

### gsize

    typedef unsigned int gsize;

An unsigned 32-bit integer intended to represent sizes of data structures.

### gssize

    typedef signed int gssize;

A signed 32-bit integer intended to represent sizes of data structures.

<<< Previous Page | Home | Up | Next Page >>>
GLib Fundamentals | Limits of Basic Types