llvm-project/llvm/lib/Support/Errno.cpp

75 lines
2.1 KiB
C++

//===- Errno.cpp - errno support --------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the errno wrappers.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Errno.h"
#include "llvm/Config/config.h"
#include <cstring>
#if HAVE_ERRNO_H
#include <errno.h>
#endif
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
namespace llvm {
namespace sys {
#if HAVE_ERRNO_H
std::string StrError() {
return StrError(errno);
}
#endif // HAVE_ERRNO_H
std::string StrError(int errnum) {
std::string str;
if (errnum == 0)
return str;
#if defined(HAVE_STRERROR_R) || HAVE_DECL_STRERROR_S
const int MaxErrStrLen = 2000;
char buffer[MaxErrStrLen];
buffer[0] = '\0';
#endif
#ifdef HAVE_STRERROR_R
// strerror_r is thread-safe.
#if defined(__GLIBC__) && defined(_GNU_SOURCE)
// glibc defines its own incompatible version of strerror_r
// which may not use the buffer supplied.
str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
#else
strerror_r(errnum, buffer, MaxErrStrLen - 1);
str = buffer;
#endif
#elif HAVE_DECL_STRERROR_S // "Windows Secure API"
strerror_s(buffer, MaxErrStrLen - 1, errnum);
str = buffer;
#elif defined(HAVE_STRERROR)
// Copy the thread un-safe result of strerror into
// the buffer as fast as possible to minimize impact
// of collision of strerror in multiple threads.
str = strerror(errnum);
#else
// Strange that this system doesn't even have strerror
// but, oh well, just use a generic message
raw_string_ostream stream(str);
stream << "Error #" << errnum;
stream.flush();
#endif
return str;
}
} // namespace sys
} // namespace llvm