lib/System/Errno.cpp

   1 //===- Errno.cpp - errno support --------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the errno wrappers.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/System/Errno.h"
  15 #include "llvm/Config/config.h"     // Get autoconf configuration settings
  16
  17 #if HAVE_STRING_H
  18 #include <string.h>
  19
  20 #if HAVE_ERRNO_H
  21 #include <errno.h>
  22 #endif
  23
  24 //===----------------------------------------------------------------------===//
  25 //=== WARNING: Implementation here must contain only TRULY operating system
  26 //===          independent code.
  27 //===----------------------------------------------------------------------===//
  28
  29 namespace llvm {
  30 namespace sys {
  31
  32 #if HAVE_ERRNO_H
  33 std::string StrError() {
  34   return StrError(errno);
  35 }
  36 #endif  // HAVE_ERRNO_H
  37
  38 std::string StrError(int errnum) {
  39   const int MaxErrStrLen = 2000;
  40   char buffer[MaxErrStrLen];
  41   buffer[0] = '\0';
  42   char* str = buffer;
  43 #ifdef HAVE_STRERROR_R
  44   // strerror_r is thread-safe.
  45   if (errnum)
  46 # if defined(__GLIBC__) && defined(_GNU_SOURCE)
  47     // glibc defines its own incompatible version of strerror_r
  48     // which may not use the buffer supplied.
  49     str = strerror_r(errnum,buffer,MaxErrStrLen-1);
  50 # else
  51     strerror_r(errnum,buffer,MaxErrStrLen-1);
  52 # endif
  53 #elif defined(HAVE_STRERROR_S)  // Windows.
  54     if (errnum)
  55       strerror_s(buffer, errnum);
  56 #elif defined(HAVE_STRERROR)
  57   // Copy the thread un-safe result of strerror into
  58   // the buffer as fast as possible to minimize impact
  59   // of collision of strerror in multiple threads.
  60   if (errnum)
  61     strncpy(buffer,strerror(errnum),MaxErrStrLen-1);
  62   buffer[MaxErrStrLen-1] = '\0';
  63 #else
  64   // Strange that this system doesn't even have strerror
  65   // but, oh well, just use a generic message
  66   sprintf(buffer, "Error #%d", errnum);
  67 #endif
  68   return str;
  69 }
  70
  71 }  // namespace sys
  72 }  // namespace llvm
  73
  74 #endif  // HAVE_STRING_H