|
|
|
GLib Reference Manual | |
|---|---|---|---|---|
#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 (ap1,ap2) #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_NULL_TERMINATED #define G_GNUC_WARN_UNUSED_RESULT #define G_GNUC_FUNCTION #define G_GNUC_PRETTY_FUNCTION #define G_GNUC_NO_INSTRUMENT #define G_HAVE_GNUC_VISIBILITY #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
This macro is used to export function prototypes so they can be linked
with an external version when no inlining is performed. The file which
implements the functions should define G_IMPLEMENTS_INLINES
before including the headers which contain G_INLINE_FUNC declarations.
Since inlining is very compiler-dependent using these macros correctly
is very difficult. Their use is strongly discouraged.
This macro is often mistaken for a replacement for the inline keyword; inline is already declared in a portable manner in the glib headers and can be used normally.
#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(ap1,ap2)
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()string.h for you.
ap1 : |
the va_list variable to place a copy of ap2 in.
|
ap2 : |
a va_list. |
#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()
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()
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()strfmon()printf()scanf()strftime()strfmon()
gchar *g_dgettext (gchar *domain_name, gchar *msgid) G_GNUC_FORMAT (2);
arg_idx : |
the index of the argument. |
#define G_GNUC_NULL_TERMINATED
Expands to the GNU C sentinel function attribute if the
compiler is gcc, or "" if it isn't. This function attribute
only applies to variadic functions and instructs the compiler to check that
the argument list is terminated with an explicit NULL.
See the GNU C documentation for details.
#define G_GNUC_WARN_UNUSED_RESULT
Expands to the GNU C warn_unused_ersult function attribute
if the compiler is gcc, or "" if it isn't. This function
attribute makes the compiler emit a warning if the result of a function call
is ignored. See the GNU C documentation for details.
Since 2.10
#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_HAVE_GNUC_VISIBILITY 1
This macro is defined as 1 if the the compiler supports ELF visibility attributes (currently only gcc).
Since: 2.6#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.
#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