Note that depending on the platform and build configuration, the format macros might not be compatible with the system provided printf() function, because GLib might use a different printf() implementation internally. The format macros will always work with GLib API (like g_print() ), and with any C99 compatible printf() implementation.

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.

Types which correspond exactly to standard C99 types, but are available to use even if your compiler does not support C99 — gsize , goffset , gintptr , guintptr .

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

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

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

New types which are not part of standard C (but are defined in various C standard library header files) — gboolean , gssize .

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

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

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

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

Types and Values

gboolean typedef gint gboolean; A standard boolean type. Variables of this type should only contain the value TRUE or FALSE . Never directly compare the contents of a gboolean variable with the values TRUE or FALSE . Use if (condition) to check a gboolean is "true", instead of if (condition == TRUE) . Likewise use if (!condition) to check a gboolean is "false". There is no validation when assigning to a gboolean variable and so it could contain any value represented by a gint. This is why the use of if (condition) is recommended. All non-zero values in C evaluate to "true".

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) (-G_MAXINT8 - 1)) 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) (-G_MAXINT16 - 1)) 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. 1 2 3 4 5 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) (-G_MAXINT32 - 1)) 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_MAXINT64 - G_GINT64_CONSTANT(1))) 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. 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. 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.

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_GUINT64_CONSTANT(0xffffffffffffffff) 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. 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.

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 32 bit wide on a 32-bit platform and 64 bit wide on a 64-bit 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. 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_GSSIZE_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_MODIFIER #define G_GSSIZE_MODIFIER "l" The platform dependent length modifier for conversion specifiers for scanning and printing values of type gssize. It is a string literal. Since: 2.6

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 POSIX type off_t as if compiling with _FILE_OFFSET_BITS set to 64. goffset is always 64 bits wide, even on 32-bit architectures. 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

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