src/llvm/lib/Support/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/Support/Errno.h"
  15 #include "llvm/Config/config.h"     // Get autoconf configuration settings
  16 #include "llvm/Support/raw_ostream.h"
  17 #include <string.h>
  18
  19 #if HAVE_ERRNO_H
  20 #include <errno.h>
  21 #endif
  22
  23 //===----------------------------------------------------------------------===//
  24 //=== WARNING: Implementation here must contain only TRULY operating system
  25 //===          independent code.
  26 //===----------------------------------------------------------------------===//
  27
  28 namespace llvm {
  29 namespace sys {
  30
  31 #if HAVE_ERRNO_H
  32 std::string StrError() {
  33   return StrError(errno);
  34 }
  35 #endif  // HAVE_ERRNO_H
  36
  37 std::string StrError(int errnum) {
  38   std::string str;
  39   if (errnum == 0)
  40     return str;
  41 #if defined(HAVE_STRERROR_R) || HAVE_DECL_STRERROR_S
  42   const int MaxErrStrLen = 2000;
  43   char buffer[MaxErrStrLen];
  44   buffer[0] = '\0';
  45 #endif
  46
  47 #ifdef HAVE_STRERROR_R
  48   // strerror_r is thread-safe.
  49 #if defined(__GLIBC__) && defined(_GNU_SOURCE)
  50   // glibc defines its own incompatible version of strerror_r
  51   // which may not use the buffer supplied.
  52   str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
  53 #else
  54   strerror_r(errnum, buffer, MaxErrStrLen - 1);
  55   str = buffer;
  56 #endif
  57 #elif HAVE_DECL_STRERROR_S // "Windows Secure API"
  58   strerror_s(buffer, MaxErrStrLen - 1, errnum);
  59   str = buffer;
  60 #elif defined(HAVE_STRERROR)
  61   // Copy the thread un-safe result of strerror into
  62   // the buffer as fast as possible to minimize impact
  63   // of collision of strerror in multiple threads.
  64   str = strerror(errnum);
  65 #else
  66   // Strange that this system doesn't even have strerror
  67   // but, oh well, just use a generic message
  68   raw_string_ostream stream(str);
  69   stream << "Error #" << errnum;
  70   stream.flush();
  71 #endif
  72   return str;
  73 }
  74
  75 }  // namespace sys
  76 }  // namespace llvm