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 #include "compiler-tests.h"
  39
  40 /*
  41  * Attributes to apply to functions and their arguments, using various
  42  * compiler-specific extensions.
  43  */
  44
  45 /*
  46  * This was introduced by Clang:
  47  *
  48  *     https://clang.llvm.org/docs/LanguageExtensions.html#has-attribute
  49  *
  50  * in some version (which version?); it has been picked up by GCC 5.0.
  51  */
  52 #ifndef __has_attribute
  53   /*
  54    * It's a macro, so you can check whether it's defined to check
  55    * whether it's supported.
  56    *
  57    * If it's not, define it to always return 0, so that we move on to
  58    * the fallback checks.
  59    */
  60   #define __has_attribute(x) 0
  61 #endif
  62
  63 /*
  64  * NORETURN, before a function declaration, means "this function
  65  * never returns".  (It must go before the function declaration, e.g.
  66  * "extern NORETURN func(...)" rather than after the function
  67  * declaration, as the MSVC version has to go before the declaration.)
  68  */
  69 #if __has_attribute(noreturn) \
  70     || ND_IS_AT_LEAST_GNUC_VERSION(2,5) \
  71     || ND_IS_AT_LEAST_SUNC_VERSION(5,9) \
  72     || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
  73     || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
  74   /*
  75    * Compiler with support for __attribute((noreturn)), or GCC 2.5 and
  76    * later, or Solaris Studio 12 (Sun C 5.9) and later, or IBM XL C 10.1
  77    * and later (do any earlier versions of XL C support this?), or
  78    * HP aCC A.06.10 and later.
  79    */
  80   #define NORETURN __attribute((noreturn))
  81
  82   /*
  83    * However, GCC didn't support that for function *pointers* until GCC
  84    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
  85    *
  86    * Sun C/Oracle Studio C doesn't seem to support it, either.
  87    */
  88   #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401)) \
  89       || (defined(__SUNPRO_C))
  90     #define NORETURN_FUNCPTR
  91   #else
  92     #define NORETURN_FUNCPTR __attribute((noreturn))
  93   #endif
  94 #elif defined(_MSC_VER)
  95   /*
  96    * MSVC.
  97    * It doesn't allow __declspec(noreturn) to be applied to function
  98    * pointers.
  99    */
 100   #define NORETURN __declspec(noreturn)
 101   #define NORETURN_FUNCPTR
 102 #else
 103   #define NORETURN
 104   #define NORETURN_FUNCPTR
 105 #endif
 106
 107 /*
 108  * PRINTFLIKE(x,y), after a function declaration, means "this function
 109  * does printf-style formatting, with the xth argument being the format
 110  * string and the yth argument being the first argument for the format
 111  * string".
 112  */
 113 #if __has_attribute(__format__) \
 114     || ND_IS_AT_LEAST_GNUC_VERSION(2,3) \
 115     || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
 116     || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
 117   /*
 118    * Compiler with support for it, or GCC 2.3 and later, or IBM XL C 10.1
 119    * and later (do any earlier versions of XL C support this?),
 120    * or HP aCC A.06.10 and later.
 121    */
 122   #define PRINTFLIKE(x,y) __attribute__((__format__(__printf__,x,y)))
 123
 124   /*
 125    * However, GCC didn't support that for function *pointers* until GCC
 126    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
 127    */
 128   #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401))
 129     #define PRINTFLIKE_FUNCPTR(x,y)
 130   #else
 131     #define PRINTFLIKE_FUNCPTR(x,y) __attribute__((__format__(__printf__,x,y)))
 132   #endif
 133 #else
 134   #define PRINTFLIKE(x,y)
 135   #define PRINTFLIKE_FUNCPTR(x,y)
 136 #endif
 137
 138 /*
 139  * For flagging arguments as format strings in MSVC.
 140  */
 141 #ifdef _MSC_VER
 142  #include <sal.h>
 143  #define FORMAT_STRING(p) _Printf_format_string_ p
 144 #else
 145  #define FORMAT_STRING(p) p
 146 #endif
 147
 148 #endif /* lib_funcattrs_h */