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
StrError()32 std::string StrError() {
33   return StrError(errno);
34 }
35 #endif  // HAVE_ERRNO_H
36 
StrError(int errnum)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
77