Miscellaneous Macros

G_INLINE_FUNC

#define     G_INLINE_FUNC

Used to declare inline functions. If inline functions are not supported on the particular platform, the macro evaluates to the empty string.

G_STMT_START

#define     G_STMT_START

Used within multi-statement macros so that they can be used in places where only one statement is expected by the compiler.

G_STMT_END

#define     G_STMT_END

Used within multi-statement macros so that they can be used in places where only one statement is expected by the compiler.

G_BEGIN_DECLS

#define     G_BEGIN_DECLS

Used (along with G_END_DECLS) to bracket header files. If the compiler in use is a C++ compiler, adds extern "C" around the header.

G_END_DECLS

#define     G_END_DECLS

Used (along with G_BEGIN_DECLS) to bracket header files. If the compiler in use is a C++ compiler, adds extern "C" around the header.

G_N_ELEMENTS()

#define G_N_ELEMENTS(arr)		(sizeof (arr) / sizeof ((arr)[0]))

Determines the number of elements in an array. The array must be declared so the compiler knows its size at compile-time; this macro will not work on an array allocated on the heap, only static arrays or arrays on the stack.

G_VA_COPY

#define     G_VA_COPY

Portable way to copy va_list variables.

In order to use this function, you must include string.h yourself, because this macro may use memmove() and GLib does not include string.h for you.

G_STRINGIFY()

#define G_STRINGIFY(macro_or_string)	G_STRINGIFY_ARG (macro_or_string)

Accepts a macro or a string and converts it into a string.

G_GNUC_EXTENSION

#define     G_GNUC_EXTENSION

Expands to __extension__ when gcc is used as the compiler. This simply tells gcc not to warn about the following non-standard code when compiling with the -pedantic option.

G_GNUC_CONST

#define     G_GNUC_CONST

Expands to the GNU C const function attribute if the compiler is gcc. Declaring a function as const enables better optimization of the function. A const function doesn't examine any values except its parameters, and has no effects except its return value. See the GNU C documentation for details.

G_GNUC_NORETURN

#define     G_GNUC_NORETURN

Expands to the GNU C noreturn function attribute if the compiler is gcc. It is used for declaring functions which never return. It enables optimization of the function, and avoids possible compiler warnings. See the GNU C documentation for details.

G_GNUC_UNUSED

#define     G_GNUC_UNUSED

Expands to the GNU C unused function attribute if the compiler is gcc. It is used for declaring functions which may never be used. It avoids possible compiler warnings. See the GNU C documentation for details.

G_GNUC_PURE

#define     G_GNUC_PURE

Expands to the GNU C pure function attribute if the compiler is gcc. Declaring a function as pure enables better optimization of the function. A pure function has no effects except its return value and the return value depends only on the parameters and/or global variables. See the GNU C documentation for details.

G_GNUC_PRINTF()

#define     G_GNUC_PRINTF( format_idx, arg_idx )

Expands to the GNU C format function attribute if the compiler is gcc. This is used for declaring functions which take a variable number of arguments, with the same syntax as printf(). It allows the compiler to type-check the arguments passed to the function. See the GNU C documentation for details.

gint g_snprintf (gchar  *string,
                 gulong       n,
                 gchar const *format,
                 ...) G_GNUC_PRINTF (3, 4);

G_GNUC_SCANF()

#define     G_GNUC_SCANF( format_idx, arg_idx )

Expands to the GNU C format function attribute if the compiler is gcc. This is used for declaring functions which take a variable number of arguments, with the same syntax as scanf(). It allows the compiler to type-check the arguments passed to the function. See the GNU C documentation for details.

G_GNUC_FORMAT()

#define     G_GNUC_FORMAT( arg_idx )

Expands to the GNU C format_arg function attribute if the compiler is gcc. This function attribute specifies that a function takes a format string for a printf(), scanf(), strftime() or strfmon() style function and modifies it, so that the result can be passed to a printf(), scanf(), strftime() or strfmon() style function (with the remaining arguments to the format function the same as they would have been for the unmodified string). See the GNU C documentation for details.

gchar *g_dgettext (gchar *domain_name, gchar *msgid) G_GNUC_FORMAT (2);

G_GNUC_FUNCTION

#define     G_GNUC_FUNCTION

Expands to the GNU C __FUNCTION__ variable if the compiler is gcc, or "" if it isn't. The GNU C __FUNCTION__ variable contains the name of the current function. See the GNU C documentation for details.

G_GNUC_PRETTY_FUNCTION

#define     G_GNUC_PRETTY_FUNCTION

Expands to the GNU C __PRETTY_FUNCTION__ variable if the compiler is gcc, or "" if it isn't. The GNU C __PRETTY_FUNCTION__ variable contains the name of the current function. For a C program this is the same as the __FUNCTION__ variable but for C++ it also includes extra information such as the class and function prototype. See the GNU C documentation for details.

G_GNUC_NO_INSTRUMENT

#define     G_GNUC_NO_INSTRUMENT

Expands to the GNU C no_instrument_function function attribute if the compiler is gcc. Functions with this attribute will not be instrumented for profiling, when the compiler is called with the -finstrument-functions option. See the GNU C documentation for details.

G_STRLOC

#define     G_STRLOC

Expands to a string identifying the current code position.

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);

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.

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.

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.

G_GINT64_FORMAT

#define G_GINT64_FORMAT "lli"

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

G_GUINT64_FORMAT

#define G_GUINT64_FORMAT "llu"

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