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Miscellaneous MacrosMiscellaneous Macros — specialized macros which are not used often. |
#include <glib.h> #define G_INLINE_FUNC #define G_STMT_START #define G_STMT_END #define G_BEGIN_DECLS #define G_END_DECLS #define G_N_ELEMENTS (arr) #define G_VA_COPY #define G_STRINGIFY (macro_or_string) #define G_GNUC_EXTENSION #define G_GNUC_CONST #define G_GNUC_PURE #define G_GNUC_MALLOC #define G_GNUC_DEPRECATED #define G_GNUC_NORETURN #define G_GNUC_UNUSED #define G_GNUC_PRINTF ( format_idx, arg_idx ) #define G_GNUC_SCANF ( format_idx, arg_idx ) #define G_GNUC_FORMAT ( arg_idx ) #define G_GNUC_FUNCTION #define G_GNUC_PRETTY_FUNCTION #define G_GNUC_NO_INSTRUMENT #define G_GNUC_INTERNAL #define G_LIKELY (expr) #define G_UNLIKELY (expr) #define G_STRLOC #define G_STRFUNC #define G_GINT16_MODIFIER #define G_GINT16_FORMAT #define G_GUINT16_FORMAT #define G_GINT32_MODIFIER #define G_GINT32_FORMAT #define G_GUINT32_FORMAT #define G_GINT64_MODIFIER #define G_GINT64_FORMAT #define G_GUINT64_FORMAT #define G_GSIZE_MODIFIER #define G_GSIZE_FORMAT #define G_GSSIZE_FORMAT
These macros provide more specialized features which are not needed so often by application programmers.
#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.
#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.
#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.
#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.
#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.
#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.
| arr : | the array |
#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.
#define G_STRINGIFY(macro_or_string) G_STRINGIFY_ARG (macro_or_string)
Accepts a macro or a string and converts it into a string.
| macro_or_string : | a macro or a string. |
#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.
#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 calls to 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.
A function that has pointer arguments and examines the data pointed to must not be declared const. Likewise, a function that calls a non-const function usually must not be const. It doesn't make sense for a const function to return void.
#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 calls to 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.
#define G_GNUC_MALLOC
Expands to the GNU C malloc function attribute if the compiler is gcc. Declaring a function as malloc enables better optimization of the function. A function can have the malloc attribute if it returns a pointer which is guaranteed to not alias with any other pointer when the function returns (in practice, this means newly allocated memory). See the GNU C documentation for details.
Since 2.6
#define G_GNUC_DEPRECATED
Expands to the GNU C deprecated attribute if the compiler is gcc. It can be used to mark typedefs, variables and functions as deprecated. When called with the -Wdeprecated option, the compiler will generate warnings when deprecated interfaces are used. See the GNU C documentation for details.
Since 2.2
#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.
#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.
#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);
| format_idx : | the index of the argument corresponding to the format string. (The arguments are numbered from 1). |
| arg_idx : | the index of the first of the format arguments. |
#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.
| format_idx : | the index of the argument corresponding to the format string. (The arguments are numbered from 1). |
| arg_idx : | the index of the first of the format arguments. |
#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);
| arg_idx : | the index of the argument. |
#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.
#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.
#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.
#define G_GNUC_INTERNAL
Expands to the GNU C visibility(hidden) attribute if the compiler supports it (currently only gcc). This attribute can be used for marking library functions as being used internally to the lib only, to not create inefficient PLT entries. Note that static functions do not need to be marked as internal in this way. See the GNU C documentation for details.
Since: 2.6#define G_LIKELY(expr)
Hints the compiler that the expression is likely to evaluate to a true value. The compiler may use this information for optimizations.
if (G_LIKELY (random() != 1))
g_print ("not one");
| expr : | the expression |
Since 2.2
#define G_UNLIKELY(expr)
Hints the compiler that the expression is unlikely to evaluate to a true value. The compiler may use this information for optimizations.
if (G_UNLIKELY (random() == 1))
g_print ("a random one");
| expr : | the expression |
Since 2.2
#define G_GINT16_MODIFIER "h"
The platform dependent length modifier for constructing printf() conversion specifiers for 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";
gint16 value = 123;
g_print ("%#" G_GINT16_MODIFIER "x", value);
Since 2.4
#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);
#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.
#define G_GINT32_MODIFIER ""
The platform dependent length modifier for constructing printf() conversion specifiers for values of type gint32 or guint32. See also G_GINT16_MODIFIER.
Since 2.4
#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.
#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.
#define G_GINT64_MODIFIER "ll"
The platform dependent length modifier for constructing printf() conversion specifiers for values of type gint64 or guint64. See also G_GINT16_MODIFIER.
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
#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.
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_strtoull() instead.
#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.
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_strtoull() instead.
#define G_GSIZE_MODIFIER ""
The platform dependent length modifier for constructing printf() conversion specifiers for values of type gsize or gssize. See also G_GINT16_MODIFIER.
Since 2.6
#define G_GSIZE_FORMAT "u"
This is the platform dependent conversion specifier for scanning and printing values of type gsize. See also G_GINT16_FORMAT.
Since 2.6
#define G_GSSIZE_FORMAT "i"
This is the platform dependent conversion specifier for scanning and printing values of type gssize. See also G_GINT16_FORMAT.
Since 2.6
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