LLVM  10.0.0svn
Errno.cpp
Go to the documentation of this file.
1 //===- Errno.cpp - errno support --------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the errno wrappers.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Support/Errno.h"
14 #include "llvm/Config/config.h"
16 #include <string.h>
17 
18 #if HAVE_ERRNO_H
19 #include <errno.h>
20 #endif
21 
22 //===----------------------------------------------------------------------===//
23 //=== WARNING: Implementation here must contain only TRULY operating system
24 //=== independent code.
25 //===----------------------------------------------------------------------===//
26 
27 namespace llvm {
28 namespace sys {
29 
30 #if HAVE_ERRNO_H
31 std::string StrError() {
32  return StrError(errno);
33 }
34 #endif // HAVE_ERRNO_H
35 
36 std::string StrError(int errnum) {
37  std::string str;
38  if (errnum == 0)
39  return str;
40 #if defined(HAVE_STRERROR_R) || HAVE_DECL_STRERROR_S
41  const int MaxErrStrLen = 2000;
42  char buffer[MaxErrStrLen];
43  buffer[0] = '\0';
44 #endif
45 
46 #ifdef HAVE_STRERROR_R
47  // strerror_r is thread-safe.
48 #if defined(__GLIBC__) && defined(_GNU_SOURCE)
49  // glibc defines its own incompatible version of strerror_r
50  // which may not use the buffer supplied.
51  str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
52 #else
53  strerror_r(errnum, buffer, MaxErrStrLen - 1);
54  str = buffer;
55 #endif
56 #elif HAVE_DECL_STRERROR_S // "Windows Secure API"
57  strerror_s(buffer, MaxErrStrLen - 1, errnum);
58  str = buffer;
59 #elif defined(HAVE_STRERROR)
60  // Copy the thread un-safe result of strerror into
61  // the buffer as fast as possible to minimize impact
62  // of collision of strerror in multiple threads.
63  str = strerror(errnum);
64 #else
65  // Strange that this system doesn't even have strerror
66  // but, oh well, just use a generic message
67  raw_string_ostream stream(str);
68  stream << "Error #" << errnum;
69  stream.flush();
70 #endif
71  return str;
72 }
73 
74 } // namespace sys
75 } // namespace llvm
This class represents lattice values for constants.
Definition: AllocatorList.h:23
std::string StrError()
Returns a string representation of the errno value, using whatever thread-safe variant of strerror() ...
Definition: Errno.cpp:31
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:482