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
28namespace llvm {
29namespace sys {
30
31#if HAVE_ERRNO_H
32std::string StrError() {
33  return StrError(errno);
34}
35#endif  // HAVE_ERRNO_H
36
37std::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
77