gmacros.h

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 /* This file must not include any other glib header file and must thus
  28  * not refer to variables from glibconfig.h
  29  */
  30
  31 #ifndef __G_MACROS_H__
  32 #define __G_MACROS_H__
  33
  34 /* Here we provide G_GNUC_EXTENSION as an alias for __extension__,
  35  * where this is valid. This allows for warningless compilation of
  36  * "long long" types even in the presence of '-ansi -pedantic'.
  37  */
  38 #if     __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)
  39 #  define G_GNUC_EXTENSION __extension__
  40 #else
  41 #  define G_GNUC_EXTENSION
  42 #endif
  43
  44 /* Provide macros to feature the GCC function attribute.
  45  */
  46 #if    __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
  47 #define G_GNUC_PURE                            \
  48   __attribute__((pure))
  49 #else
  50 #define G_GNUC_PURE
  51 #endif
  52
  53 #if     __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 4)
  54 #define G_GNUC_PRINTF( format_idx, arg_idx )    \
  55   __attribute__((format (printf, format_idx, arg_idx)))
  56 #define G_GNUC_SCANF( format_idx, arg_idx )     \
  57   __attribute__((format (scanf, format_idx, arg_idx)))
  58 #define G_GNUC_FORMAT( arg_idx )                \
  59   __attribute__((format_arg (arg_idx)))
  60 #define G_GNUC_NORETURN                         \
  61   __attribute__((noreturn))
  62 #define G_GNUC_CONST                            \
  63   __attribute__((const))
  64 #define G_GNUC_UNUSED                           \
  65   __attribute__((unused))
  66 #else   /* !__GNUC__ */
  67 #define G_GNUC_PRINTF( format_idx, arg_idx )
  68 #define G_GNUC_SCANF( format_idx, arg_idx )
  69 #define G_GNUC_FORMAT( arg_idx )
  70 #define G_GNUC_NORETURN
  71 #define G_GNUC_CONST
  72 #define G_GNUC_UNUSED
  73 #endif  /* !__GNUC__ */
  74
  75 /* Wrap the gcc __PRETTY_FUNCTION__ and __FUNCTION__ variables with
  76  * macros, so we can refer to them as strings unconditionally.
  77  */
  78 #ifdef  __GNUC__
  79 #define G_GNUC_FUNCTION         __FUNCTION__
  80 #define G_GNUC_PRETTY_FUNCTION  __PRETTY_FUNCTION__
  81 #else   /* !__GNUC__ */
  82 #define G_GNUC_FUNCTION         ""
  83 #define G_GNUC_PRETTY_FUNCTION  ""
  84 #endif  /* !__GNUC__ */
  85
  86 #define G_STRINGIFY(macro_or_string)    G_STRINGIFY_ARG (macro_or_string)
  87 #define G_STRINGIFY_ARG(contents)       #contents
  88
  89 /* Provide a string identifying the current code position */
  90 #ifdef  __GNUC__
  91 #  define G_STRLOC      __FILE__ ":" G_STRINGIFY (__LINE__) ":" __PRETTY_FUNCTION__ "()"
  92 #else
  93 #  define G_STRLOC      __FILE__ ":" G_STRINGIFY (__LINE__)
  94 #endif
  95
  96 /* Guard C code in headers, while including them from C++ */
  97 #ifdef  __cplusplus
  98 # define G_BEGIN_DECLS  extern "C" {
  99 # define G_END_DECLS    }
 100 #else
 101 # define G_BEGIN_DECLS
 102 # define G_END_DECLS
 103 #endif
 104
 105 /* Provide definitions for some commonly used macros.
 106  *  Some of them are only provided if they haven't already
 107  *  been defined. It is assumed that if they are already
 108  *  defined then the current definition is correct.
 109  */
 110 #ifndef NULL
 111 #  ifdef __cplusplus
 112 #    define NULL        (0L)
 113 #  else /* !__cplusplus */
 114 #    define NULL        ((void*) 0)
 115 #  endif /* !__cplusplus */
 116 #endif
 117
 118 #ifndef FALSE
 119 #define FALSE   (0)
 120 #endif
 121
 122 #ifndef TRUE
 123 #define TRUE    (!FALSE)
 124 #endif
 125
 126 #undef  MAX
 127 #define MAX(a, b)  (((a) > (b)) ? (a) : (b))
 128
 129 #undef  MIN
 130 #define MIN(a, b)  (((a) < (b)) ? (a) : (b))
 131
 132 #undef  ABS
 133 #define ABS(a)     (((a) < 0) ? -(a) : (a))
 134
 135 #undef  CLAMP
 136 #define CLAMP(x, low, high)  (((x) > (high)) ? (high) : (((x) < (low)) ? (low) : (x)))
 137
 138 /* Count the number of elements in an array. The array must be defined
 139  * as such; using this with a dynamically allocated array will give
 140  * incorrect results.
 141  */
 142 #define G_N_ELEMENTS(arr)               (sizeof (arr) / sizeof ((arr)[0]))
 143
 144 /* Provide convenience macros for handling structure
 145  * fields through their offsets.
 146  */
 147 #define G_STRUCT_OFFSET(struct_type, member)    \
 148     ((glong) ((guint8*) &((struct_type*) 0)->member))
 149 #define G_STRUCT_MEMBER_P(struct_p, struct_offset)   \
 150     ((gpointer) ((guint8*) (struct_p) + (glong) (struct_offset)))
 151 #define G_STRUCT_MEMBER(member_type, struct_p, struct_offset)   \
 152     (*(member_type*) G_STRUCT_MEMBER_P ((struct_p), (struct_offset)))
 153
 154 /* Provide simple macro statement wrappers (adapted from Perl):
 155  *  G_STMT_START { statements; } G_STMT_END;
 156  *  can be used as a single statement, as in
 157  *  if (x) G_STMT_START { ... } G_STMT_END; else ...
 158  *
 159  *  For gcc we will wrap the statements within `({' and `})' braces.
 160  *  For SunOS they will be wrapped within `if (1)' and `else (void) 0',
 161  *  and otherwise within `do' and `while (0)'.
 162  */
 163 #if !(defined (G_STMT_START) && defined (G_STMT_END))
 164 #  if defined (__GNUC__) && !defined (__STRICT_ANSI__) && !defined (__cplusplus)
 165 #    define G_STMT_START        (void)(
 166 #    define G_STMT_END          )
 167 #  else
 168 #    if (defined (sun) || defined (__sun__))
 169 #      define G_STMT_START      if (1)
 170 #      define G_STMT_END        else (void)0
 171 #    else
 172 #      define G_STMT_START      do
 173 #      define G_STMT_END        while (0)
 174 #    endif
 175 #  endif
 176 #endif
 177
 178 /* Allow the app programmer to select whether or not return values
 179  * (usually char*) are const or not.  Don't try using this feature for
 180  * functions with C++ linkage.
 181  */
 182 #ifdef G_DISABLE_CONST_RETURNS
 183 #define G_CONST_RETURN
 184 #else
 185 #define G_CONST_RETURN const
 186 #endif
 187
 188 #endif /* __G_MACROS_H__ */