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  const int MaxErrStrLen = 2000;
39  char buffer[MaxErrStrLen];
40  buffer[0] = '\0';
41  std::string str;
42  if (errnum == 0)
43    return str;
44
45#ifdef HAVE_STRERROR_R
46  // strerror_r is thread-safe.
47#if defined(__GLIBC__) && defined(_GNU_SOURCE)
48  // glibc defines its own incompatible version of strerror_r
49  // which may not use the buffer supplied.
50  str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
51#else
52  strerror_r(errnum, buffer, MaxErrStrLen - 1);
53  str = buffer;
54#endif
55#elif HAVE_DECL_STRERROR_S // "Windows Secure API"
56  strerror_s(buffer, MaxErrStrLen - 1, errnum);
57  str = buffer;
58#elif defined(HAVE_STRERROR)
59  // Copy the thread un-safe result of strerror into
60  // the buffer as fast as possible to minimize impact
61  // of collision of strerror in multiple threads.
62  str = strerror(errnum);
63#else
64  // Strange that this system doesn't even have strerror
65  // but, oh well, just use a generic message
66  raw_string_ostream stream(str);
67  stream << "Error #" << errnum;
68  stream.flush();
69#endif
70  return str;
71}
72
73}  // namespace sys
74}  // namespace llvm
75