The Tcpdump Group git mirrors - tcpdump/blob - funcattrs.h

   1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
   2 /*
   3  * Copyright (c) 1993, 1994, 1995, 1996, 1997
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by the Computer Systems
  17  *      Engineering Group at Lawrence Berkeley Laboratory.
  18  * 4. Neither the name of the University nor of the Laboratory may be used
  19  *    to endorse or promote products derived from this software without
  20  *    specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef lib_funcattrs_h
  36 #define lib_funcattrs_h
  37
  38 /*
  39  * Attributes to apply to functions and their arguments, using various
  40  * compiler-specific extensions.
  41  */
  42
  43 /*
  44  * This was introduced by Clang:
  45  *
  46  *     http://clang.llvm.org/docs/LanguageExtensions.html#has-attribute
  47  *
  48  * in some version (which version?); it has been picked up by GCC 5.0.
  49  */
  50 #ifndef __has_attribute
  51   /*
  52    * It's a macro, so you can check whether it's defined to check
  53    * whether it's supported.
  54    *
  55    * If it's not, define it to always return 0, so that we move on to
  56    * the fallback checks.
  57    */
  58   #define __has_attribute(x) 0
  59 #endif
  60
  61 /*
  62  * NORETURN, before a function declaration, means "this function
  63  * never returns".  (It must go before the function declaration, e.g.
  64  * "extern NORETURN func(...)" rather than after the function
  65  * declaration, as the MSVC version has to go before the declaration.)
  66  */
  67 #if __has_attribute(noreturn) \
  68     || (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 205)) \
  69     || (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x590)) \
  70     || (defined(__xlC__) && __xlC__ >= 0x0A01) \
  71     || (defined(__HP_aCC) && __HP_aCC >= 61000)
  72   /*
  73    * Compiler with support for __attribute((noreturn)), or GCC 2.5 and
  74    * later, or Solaris Studio 12 (Sun C 5.9) and later, or IBM XL C 10.1
  75    * and later (do any earlier versions of XL C support this?), or
  76    * HP aCC A.06.10 and later.
  77    */
  78   #define NORETURN __attribute((noreturn))
  79
  80   /*
  81    * However, GCC didn't support that for function *pointers* until GCC
  82    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
  83    *
  84    * Sun C/Oracle Studio C doesn't seem to support it, either.
  85    */
  86   #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401)) \
  87       || (defined(__SUNPRO_C))
  88     #define NORETURN_FUNCPTR
  89   #else
  90     #define NORETURN_FUNCPTR __attribute((noreturn))
  91   #endif
  92 #elif defined(_MSC_VER)
  93   /*
  94    * MSVC.
  95    * It doesn't allow __declspec(noreturn) to be applied to function
  96    * pointers.
  97    */
  98   #define NORETURN __declspec(noreturn)
  99   #define NORETURN_FUNCPTR
 100 #else
 101   #define NORETURN
 102   #define NORETURN_FUNCPTR
 103 #endif
 104
 105 /*
 106  * PRINTFLIKE(x,y), after a function declaration, means "this function
 107  * does printf-style formatting, with the xth argument being the format
 108  * string and the yth argument being the first argument for the format
 109  * string".
 110  */
 111 #if __has_attribute(__format__) \
 112     || (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 203)) \
 113     || (defined(__xlC__) && __xlC__ >= 0x0A01) \
 114     || (defined(__HP_aCC) && __HP_aCC >= 61000)
 115   /*
 116    * Compiler with support for it, or GCC 2.3 and later, or IBM XL C 10.1
 117    * and later (do any earlier versions of XL C support this?),
 118    * or HP aCC A.06.10 and later.
 119    */
 120   #define PRINTFLIKE(x,y) __attribute__((__format__(__printf__,x,y)))
 121
 122   /*
 123    * However, GCC didn't support that for function *pointers* until GCC
 124    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
 125    */
 126   #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401))
 127     #define PRINTFLIKE_FUNCPTR(x,y)
 128   #else
 129     #define PRINTFLIKE_FUNCPTR(x,y) __attribute__((__format__(__printf__,x,y)))
 130   #endif
 131 #else
 132   #define PRINTFLIKE(x,y)
 133   #define PRINTFLIKE_FUNCPTR(x,y)
 134 #endif
 135
 136 /*
 137  * For flagging arguments as format strings in MSVC.
 138  */
 139 #if _MSC_VER >= 1400
 140  #include <sal.h>
 141  #if _MSC_VER > 1400
 142   #define FORMAT_STRING(p) _Printf_format_string_ p
 143  #else
 144   #define FORMAT_STRING(p) __format_string p
 145  #endif
 146 #else
 147  #define FORMAT_STRING(p) p
 148 #endif
 149
 150 #endif /* lib_funcattrs_h */