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"
15#include <cstring>
16#include <errno.h>
17
18//===----------------------------------------------------------------------===//
19//=== WARNING: Implementation here must contain only TRULY operating system
20//=== independent code.
21//===----------------------------------------------------------------------===//
22
23namespace llvm {
24namespace sys {
25
26std::string StrError() {
27 return StrError(errno);
28}
29
30std::string StrError(int errnum) {
31 std::string str;
32 if (errnum == 0)
33 return str;
34#if defined(HAVE_STRERROR_R) || HAVE_DECL_STRERROR_S
35 const int MaxErrStrLen = 2000;
36 char buffer[MaxErrStrLen];
37 buffer[0] = '\0';
38#endif
39
40#ifdef HAVE_STRERROR_R
41 // strerror_r is thread-safe.
42#if defined(__GLIBC__) && defined(_GNU_SOURCE)
43 // glibc defines its own incompatible version of strerror_r
44 // which may not use the buffer supplied.
45 str = strerror_r(errnum: errnum, buf: buffer, buflen: MaxErrStrLen - 1);
46#else
47 strerror_r(errnum, buffer, MaxErrStrLen - 1);
48 str = buffer;
49#endif
50#elif HAVE_DECL_STRERROR_S // "Windows Secure API"
51 strerror_s(buffer, MaxErrStrLen - 1, errnum);
52 str = buffer;
53#else
54 // Copy the thread un-safe result of strerror into
55 // the buffer as fast as possible to minimize impact
56 // of collision of strerror in multiple threads.
57 str = strerror(errnum);
58#endif
59 return str;
60}
61
62} // namespace sys
63} // namespace llvm
64