Basic Types

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;
#define             G_MININT
#define             G_MAXINT
typedef             guint;
#define             G_MAXUINT
typedef             gshort;
#define             G_MINSHORT
#define             G_MAXSHORT
typedef             gushort;
#define             G_MAXUSHORT
typedef             glong;
#define             G_MINLONG
#define             G_MAXLONG
typedef             gulong;
#define             G_MAXULONG

typedef             gint8;
#define             G_MININT8
#define             G_MAXINT8
typedef             guint8;
#define             G_MAXUINT8
typedef             gint16;
#define             G_MININT16
#define             G_MAXINT16
#define             G_GINT16_MODIFIER
#define             G_GINT16_FORMAT
typedef             guint16;
#define             G_MAXUINT16
#define             G_GUINT16_FORMAT
typedef             gint32;
#define             G_MININT32
#define             G_MAXINT32
#define             G_GINT32_MODIFIER
#define             G_GINT32_FORMAT
typedef             guint32;
#define             G_MAXUINT32
#define             G_GUINT32_FORMAT
typedef             gint64;
#define             G_MININT64
#define             G_MAXINT64
#define             G_GINT64_MODIFIER
#define             G_GINT64_FORMAT
#define             G_GINT64_CONSTANT                   (val)
typedef             guint64;
#define             G_MAXUINT64
#define             G_GUINT64_FORMAT
#define             G_GUINT64_CONSTANT                  (val)

typedef             gfloat;
#define             G_MINFLOAT
#define             G_MAXFLOAT
typedef             gdouble;
#define             G_MINDOUBLE
#define             G_MAXDOUBLE

typedef             gsize;
#define             G_MAXSIZE
#define             G_GSIZE_MODIFIER
#define             G_GSIZE_FORMAT
typedef             gssize;
#define             G_MINSSIZE
#define             G_MAXSSIZE
#define             G_GSSIZE_FORMAT
typedef             goffset;
#define             G_MINOFFSET
#define             G_MAXOFFSET
#define             G_GOFFSET_MODIFIER
#define             G_GOFFSET_FORMAT
#define             G_GOFFSET_CONSTANT                  (val)

typedef             gintptr;
#define             G_GINTPTR_MODIFIER
#define             G_GINTPTR_FORMAT
typedef             guintptr;
#define             G_GUINTPTR_FORMAT

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 (but are defined in various C standard library header files) - gboolean, gsize, gssize, goffset, gintptr, guintptr.
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.

GLib also defines macros for the limits of some of the standard integer and floating point types, as well as macros for suitable printf() formats for these types.

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.

G_MININT

#define G_MININT INT_MIN

The minimum value which can be held in a gint.

G_MAXINT

#define G_MAXINT INT_MAX

The maximum value which can be held in a gint.

guint

typedef unsigned int    guint;

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

G_MAXUINT

#define G_MAXUINT UINT_MAX

The maximum value which can be held in a guint.

gshort

typedef short  gshort;

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

G_MINSHORT

#define G_MINSHORT SHRT_MIN

The minimum value which can be held in a gshort.

G_MAXSHORT

#define G_MAXSHORT SHRT_MAX

The maximum value which can be held in a gshort.

gushort

typedef unsigned short  gushort;

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

G_MAXUSHORT

#define G_MAXUSHORT USHRT_MAX

The maximum value which can be held in a gushort.

glong

typedef long   glong;

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

G_MINLONG

#define G_MINLONG LONG_MIN

The minimum value which can be held in a glong.

G_MAXLONG

#define G_MAXLONG LONG_MAX

The maximum value which can be held in a glong.

gulong

typedef unsigned long   gulong;

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

G_MAXULONG

#define G_MAXULONG ULONG_MAX

The maximum value which can be held in a gulong.

gint8

typedef signed char gint8;

A signed integer guaranteed to be 8 bits on all platforms. Values of this type can range from G_MININT8 (= -128) to G_MAXINT8 (= 127).

G_MININT8

#define G_MININT8 ((gint8)  0x80)

The minimum value which can be held in a gint8.

Since 2.4

G_MAXINT8

#define G_MAXINT8 ((gint8)  0x7f)

The maximum value which can be held in a gint8.

Since 2.4

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 G_MAXUINT8 (= 255).

G_MAXUINT8

#define G_MAXUINT8 ((guint8) 0xff)

The maximum value which can be held in a guint8.

Since 2.4

gint16

typedef signed short gint16;

A signed integer guaranteed to be 16 bits on all platforms. Values of this type can range from G_MININT16 (= -32,768) to G_MAXINT16 (= 32,767).

To print or scan values of this type, use G_GINT16_MODIFIER and/or G_GINT16_FORMAT.

G_MININT16

#define G_MININT16 ((gint16)  0x8000)

The minimum value which can be held in a gint16.

Since 2.4

G_MAXINT16

#define G_MAXINT16 ((gint16)  0x7fff)

The maximum value which can be held in a gint16.

Since 2.4

G_GINT16_MODIFIER

#define G_GINT16_MODIFIER "h"

The platform dependent length modifier for conversion specifiers for scanning and printing values of type gint16 or guint16. It is a string literal, but doesn't include the percent-sign, such that you can add precision and length modifiers between percent-sign and conversion specifier and append a conversion specifier.

The following example prints "0x7b";

1 2	gint16 value = 123; g_print ("%#" G_GINT16_MODIFIER "x", value);

Since 2.4

G_GINT16_FORMAT

#define G_GINT16_FORMAT "hi"

This is the platform dependent conversion specifier for scanning and printing values of type gint16. It is a string literal, but doesn't include the percent-sign, such that you can add precision and length modifiers between percent-sign and conversion specifier.

gint16 in;
gint32 out;
sscanf ("42", "%" G_GINT16_FORMAT, &in)
out = in * 1000;
g_print ("%" G_GINT32_FORMAT, out);

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 G_MAXUINT16 (= 65,535).

To print or scan values of this type, use G_GINT16_MODIFIER and/or G_GUINT16_FORMAT.

G_MAXUINT16

#define G_MAXUINT16 ((guint16) 0xffff)

The maximum value which can be held in a guint16.

Since 2.4

G_GUINT16_FORMAT

#define G_GUINT16_FORMAT "hu"

This is the platform dependent conversion specifier for scanning and printing values of type guint16. See also G_GINT16_FORMAT

gint32

typedef signed int gint32;

A signed integer guaranteed to be 32 bits on all platforms. Values of this type can range from G_MININT32 (= -2,147,483,648) to G_MAXINT32 (= 2,147,483,647).

To print or scan values of this type, use G_GINT32_MODIFIER and/or G_GINT32_FORMAT.

G_MININT32

#define G_MININT32 ((gint32)  0x80000000)

The minimum value which can be held in a gint32.

Since 2.4

G_MAXINT32

#define G_MAXINT32 ((gint32)  0x7fffffff)

The maximum value which can be held in a gint32.

Since 2.4

G_GINT32_MODIFIER

#define G_GINT32_MODIFIER ""

The platform dependent length modifier for conversion specifiers for scanning and printing values of type gint32 or guint32. It is a string literal. See also G_GINT16_MODIFIER.

Since 2.4

G_GINT32_FORMAT

#define G_GINT32_FORMAT "i"

This is the platform dependent conversion specifier for scanning and printing values of type gint32. See also G_GINT16_FORMAT.

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 G_MAXUINT32 (= 4,294,967,295).

To print or scan values of this type, use G_GINT32_MODIFIER and/or G_GUINT32_FORMAT.

G_MAXUINT32

#define G_MAXUINT32 ((guint32) 0xffffffff)

The maximum value which can be held in a guint32.

Since 2.4

G_GUINT32_FORMAT

#define G_GUINT32_FORMAT "u"

This is the platform dependent conversion specifier for scanning and printing values of type guint32. See also G_GINT16_FORMAT.

gint64

typedef signed long gint64;

A signed integer guaranteed to be 64 bits on all platforms. Values of this type can range from G_MININT64 (= -9,223,372,036,854,775,808) to G_MAXINT64 (= 9,223,372,036,854,775,807).

To print or scan values of this type, use G_GINT64_MODIFIER and/or G_GINT64_FORMAT.

G_MININT64

#define G_MININT64 ((gint64) G_GINT64_CONSTANT(0x8000000000000000))

The minimum value which can be held in a gint64.

G_MAXINT64

#define G_MAXINT64 G_GINT64_CONSTANT(0x7fffffffffffffff)

The maximum value which can be held in a gint64.

G_GINT64_MODIFIER

#define G_GINT64_MODIFIER "l"

The platform dependent length modifier for conversion specifiers for scanning and printing values of type gint64 or guint64. It is a string literal.

Note

Some platforms do not support printing 64 bit integers, even though the types are supported. On such platforms G_GINT64_MODIFIER is not defined.

Since 2.4

G_GINT64_FORMAT

#define G_GINT64_FORMAT "li"

This is the platform dependent conversion specifier for scanning and printing values of type gint64. See also G_GINT16_FORMAT.

Note

Some platforms do not support scanning and printing 64 bit integers, even though the types are supported. On such platforms G_GINT64_FORMAT is not defined. Note that scanf() may not support 64 bit integers, even if G_GINT64_FORMAT is defined. Due to its weak error handling, scanf() is not recommended for parsing anyway; consider using g_ascii_strtoull() instead.

G_GINT64_CONSTANT()

#define G_GINT64_CONSTANT(val) (val##L)

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

val :

a literal integer value, e.g. 0x1d636b02300a7aa7

guint64

typedef unsigned long guint64;

An unsigned integer guaranteed to be 64 bits on all platforms. Values of this type can range from 0 to G_MAXUINT64 (= 18,446,744,073,709,551,615).

To print or scan values of this type, use G_GINT64_MODIFIER and/or G_GUINT64_FORMAT.

G_MAXUINT64

#define G_MAXUINT64 G_GINT64_CONSTANT(0xffffffffffffffffU)

The maximum value which can be held in a guint64.

G_GUINT64_FORMAT

#define G_GUINT64_FORMAT "lu"

This is the platform dependent conversion specifier for scanning and printing values of type guint64. See also G_GINT16_FORMAT.

Note

Some platforms do not support scanning and printing 64 bit integers, even though the types are supported. On such platforms G_GUINT64_FORMAT is not defined. Note that scanf() may not support 64 bit integers, even if G_GINT64_FORMAT is defined. Due to its weak error handling, scanf() is not recommended for parsing anyway; consider using g_ascii_strtoull() instead.

G_GUINT64_CONSTANT()

#define G_GUINT64_CONSTANT(val) (val##UL)

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

val :

a literal integer value, e.g. 0x1d636b02300a7aa7U

Since 2.10

gfloat

typedef float   gfloat;

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

G_MINFLOAT

#define G_MINFLOAT FLT_MIN

The minimum positive value which can be held in a gfloat.

If you are interested in the smallest value which can be held in a gfloat, use -G_MAXFLOAT.

G_MAXFLOAT

#define G_MAXFLOAT FLT_MAX

The maximum value which can be held in a gfloat.

gdouble

typedef double  gdouble;

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

G_MINDOUBLE

#define G_MINDOUBLE DBL_MIN

The minimum positive value which can be held in a gdouble.

If you are interested in the smallest value which can be held in a gdouble, use -G_MAXDOUBLE.

G_MAXDOUBLE

#define G_MAXDOUBLE DBL_MAX

The maximum value which can be held in a gdouble.

gsize

typedef unsigned long gsize;

An unsigned integer type of the result of the sizeof operator, corresponding to the size_t type defined in C99. This type is wide enough to hold the numeric value of a pointer, so it is usually 32bit wide on a 32bit platform and 64bit wide on a 64bit platform. Values of this type can range from 0 to G_MAXSIZE.

To print or scan values of this type, use G_GSIZE_MODIFIER and/or G_GSIZE_FORMAT.

G_MAXSIZE

#define G_MAXSIZE G_MAXULONG

The maximum value which can be held in a gsize.

Since 2.4

G_GSIZE_MODIFIER

#define G_GSIZE_MODIFIER "l"

The platform dependent length modifier for conversion specifiers for scanning and printing values of type gsize or gssize. It is a string literal.

Since 2.6

G_GSIZE_FORMAT

#define G_GSIZE_FORMAT "lu"

This is the platform dependent conversion specifier for scanning and printing values of type gsize. See also G_GINT16_FORMAT.

Since 2.6

gssize

typedef signed long gssize;

A signed variant of gsize, corresponding to the ssize_t defined on most platforms. Values of this type can range from G_MINSSIZE to G_MAXSSIZE.

To print or scan values of this type, use G_GSIZE_MODIFIER and/or G_GSSIZE_FORMAT.

G_MINSSIZE

#define G_MINSSIZE G_MINLONG

The minimum value which can be held in a gssize.

Since 2.14

G_MAXSSIZE

#define G_MAXSSIZE G_MAXLONG

The maximum value which can be held in a gssize.

Since 2.14

G_GSSIZE_FORMAT

#define G_GSSIZE_FORMAT "li"

This is the platform dependent conversion specifier for scanning and printing values of type gssize. See also G_GINT16_FORMAT.

Since 2.6

goffset

typedef gint64 goffset;

A signed integer type that is used for file offsets, corresponding to the C99 type off64_t. Values of this type can range from G_MINOFFSET to G_MAXOFFSET.

To print or scan values of this type, use G_GOFFSET_MODIFIER and/or G_GOFFSET_FORMAT.

Since 2.14

G_MINOFFSET

#define G_MINOFFSET G_MININT64

The minimum value which can be held in a goffset.

G_MAXOFFSET

#define G_MAXOFFSET G_MAXINT64

The maximum value which can be held in a goffset.

G_GOFFSET_MODIFIER

#define G_GOFFSET_MODIFIER      G_GINT64_MODIFIER

The platform dependent length modifier for conversion specifiers for scanning and printing values of type goffset. It is a string literal. See also G_GINT64_MODIFIER.

Since 2.20

G_GOFFSET_FORMAT

#define G_GOFFSET_FORMAT        G_GINT64_FORMAT

This is the platform dependent conversion specifier for scanning and printing values of type goffset. See also G_GINT64_FORMAT.

Since 2.20

G_GOFFSET_CONSTANT()

#define G_GOFFSET_CONSTANT(val) G_GINT64_CONSTANT(val)

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

gintptr

typedef signed long gintptr;

Corresponds to the C99 type intptr_t, a signed integer type that can hold any pointer.

To print or scan values of this type, use G_GINTPTR_MODIFIER and/or G_GINTPTR_FORMAT.

Since 2.18

G_GINTPTR_MODIFIER

#define G_GINTPTR_MODIFIER      "l"

The platform dependent length modifier for conversion specifiers for scanning and printing values of type gintptr or guintptr. It is a string literal.

Since 2.22

G_GINTPTR_FORMAT

#define G_GINTPTR_FORMAT        "li"

This is the platform dependent conversion specifier for scanning and printing values of type gintptr.

Since 2.22

guintptr

typedef unsigned long guintptr;

Corresponds to the C99 type uintptr_t, an unsigned integer type that can hold any pointer.

To print or scan values of this type, use G_GINTPTR_MODIFIER and/or G_GUINTPTR_FORMAT.

Since 2.18

G_GUINTPTR_FORMAT

#define G_GUINTPTR_FORMAT       "lu"

This is the platform dependent conversion specifier for scanning and printing values of type guintptr.

Since 2.22

			GLib Reference Manual
Top \| Description