lib/System/Unix/Unix.h

//===- llvm/System/Unix/Unix.h - Common Unix Include File -------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines things specific to Unix implementations.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SYSTEM_UNIX_UNIX_H
#define LLVM_SYSTEM_UNIX_UNIX_H

//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only generic UNIX code that
//===          is guaranteed to work on all UNIX variants.
//===----------------------------------------------------------------------===//

#include "llvm/Config/config.h"     // Get autoconf configuration settings
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cerrno>
#include <string>
#include <algorithm>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifdef HAVE_ASSERT_H
#include <assert.h>
#endif

#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif

#ifndef WEXITSTATUS
# define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
#endif

#ifndef WIFEXITED
# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
#endif

/// This function builds an error message into \p ErrMsg using the \p prefix
/// string and the Unix error number given by \p errnum. If errnum is -1, the
/// default then the value of errno is used.
/// @brief Make an error message
///
/// If the error number can be converted to a string, it will be
/// separated from prefix by ": ".
static inline bool MakeErrMsg(
  std::string* ErrMsg, const std::string& prefix, int errnum = -1) {
  if (!ErrMsg)
    return true;
  char buffer[MAXPATHLEN];
  buffer[0] = 0;
  char* str = buffer;
  if (errnum == -1)
    errnum = errno;
#ifdef HAVE_STRERROR_R
  // strerror_r is thread-safe.
  if (errnum)
# 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,MAXPATHLEN-1);
# else
    strerror_r(errnum,buffer,MAXPATHLEN-1);
# endif
#elif 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.
  if (errnum)
    strncpy(buffer,strerror(errnum),MAXPATHLEN-1);
  buffer[MAXPATHLEN-1] = 0;
#else
  // Strange that this system doesn't even have strerror
  // but, oh well, just use a generic message
  sprintf(buffer, "Error #%d", errnum);
#endif
  *ErrMsg = prefix + ": " + str;
  return true;
}

#endif