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  * NORETURN, before a function declaration, means "this function
  47  * never returns".  (It must go before the function declaration, e.g.
  48  * "extern NORETURN func(...)" rather than after the function
  49  * declaration, as the MSVC version has to go before the declaration.)
  50  */
  51 #if __has_attribute(noreturn) \
  52     || ND_IS_AT_LEAST_GNUC_VERSION(2,5) \
  53     || ND_IS_AT_LEAST_SUNC_VERSION(5,9) \
  54     || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
  55     || ND_IS_AT_LEAST_HP_C_VERSION(6,10) \
  56     || __TINYC__
  57   /*
  58    * Compiler with support for __attribute((noreturn)), or GCC 2.5 and
  59    * later, or some compiler asserting compatibility with GCC 2.5 and
  60    * later, or Solaris Studio 12 (Sun C 5.9) and later, or IBM XL C 10.1
  61    * and later (do any earlier versions of XL C support this?), or HP aCC
  62    * A.06.10 and later, or current TinyCC.
  63    */
  64   #define NORETURN __attribute((noreturn))
  65
  66   /*
  67    * However, GCC didn't support that for function *pointers* until GCC
  68    * 4.1.0; see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3481.
  69    *
  70    * Sun C/Oracle Studio C doesn't seem to support it, either.
  71    */
  72   #if (defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) < 401)) \
  73       || (defined(__SUNPRO_C))
  74     #define NORETURN_FUNCPTR
  75   #else
  76     #define NORETURN_FUNCPTR __attribute((noreturn))
  77   #endif
  78 #elif defined(_MSC_VER)
  79   /*
  80    * MSVC.
  81    * It doesn't allow __declspec(noreturn) to be applied to function
  82    * pointers.
  83    */
  84   #define NORETURN __declspec(noreturn)
  85   #define NORETURN_FUNCPTR
  86 #else
  87   #define NORETURN
  88   #define NORETURN_FUNCPTR
  89 #endif
  90
  91 /*
  92  * WARN_UNUSED_RESULT, before a function declaration, means "the caller
  93  * should use the result of this function" (even if it's just a success/
  94  * failure indication).
  95  */
  96 #if __has_attribute(warn_unused_result) \
  97     || ND_IS_AT_LEAST_GNUC_VERSION(3,4) \
  98     || ND_IS_AT_LEAST_HP_C_VERSION(6,25)
  99   #define WARN_UNUSED_RESULT __attribute((warn_unused_result))
 100 #else
 101   #define WARN_UNUSED_RESULT
 102 #endif
 103
 104 /*
 105  * PRINTFLIKE(x,y), after a function declaration, means "this function
 106  * does printf-style formatting, with the xth argument being the format
 107  * string and the yth argument being the first argument for the format
 108  * string".
 109  */
 110 #if __has_attribute(__format__) \
 111     || ND_IS_AT_LEAST_GNUC_VERSION(2,3) \
 112     || ND_IS_AT_LEAST_XL_C_VERSION(10,1) \
 113     || ND_IS_AT_LEAST_HP_C_VERSION(6,10)
 114   /*
 115    * Compiler with support for it, or GCC 2.3 and later, or some compiler
 116    * asserting compatibility with 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    * XL C 16.1 (and possibly some earlier versions, but not 12.1 or 13.1) has
 126    * a similar bug, the bugfix for which was made in:
 127    * * version 16.1.1.8 for Linux (25 June 2020), which fixes
 128    *   https://www.ibm.com/support/pages/apar/LI81402
 129    * * version 16.1.0.5 for AIX (5 May 2020), which fixes
 130    *   https://www.ibm.com/support/pages/apar/IJ24678
 131    *
 132    * When testing versions, keep in mind that XL C 16.1 pretends to be both
 133    * GCC 4.2 and Clang 4.0 at once.
 134    */
 135   #if (ND_IS_AT_LEAST_GNUC_VERSION(4,1) \
 136        && !ND_IS_AT_LEAST_XL_C_VERSION(10,1)) \
 137       || (ND_IS_AT_LEAST_XL_C_VERSION(16,1) \
 138           && (ND_IS_AT_LEAST_XL_C_MODFIX(1, 8) && defined(__linux__)) \
 139               || (ND_IS_AT_LEAST_XL_C_MODFIX(0, 5) && defined(_AIX)))
 140     #define PRINTFLIKE_FUNCPTR(x,y) __attribute__((__format__(__printf__,x,y)))
 141   #endif
 142 #endif
 143
 144 #if !defined(PRINTFLIKE)
 145 #define PRINTFLIKE(x,y)
 146 #endif
 147 #if !defined(PRINTFLIKE_FUNCPTR)
 148 #define PRINTFLIKE_FUNCPTR(x,y)
 149 #endif
 150
 151 /*
 152  * For flagging arguments as format strings in MSVC.
 153  */
 154 #ifdef _MSC_VER
 155  #include <sal.h>
 156  #define FORMAT_STRING(p) _Printf_format_string_ p
 157 #else
 158  #define FORMAT_STRING(p) p
 159 #endif
 160
 161 #endif /* lib_funcattrs_h */