Get path of executable

问题:

I know this question has been asked before but I still haven\'t seen a satisfactory answer, or a definitive \"no, this cannot be done\", so I\'ll ask again!

All I want to do is get the path to the currently running executable, either as an absolute path or relative to where the executable is invoked from, in a platform-independent fashion. I though boost::filesystem::initial_path was the answer to my troubles but that seems to only handle the \'platform-independent\' part of the question - it still returns the path from which the application was invoked.

For a bit of background, this is a game using Ogre, which I\'m trying to profile using Very Sleepy, which runs the target executable from its own directory, so of course on load the game finds no configuration files etc. and promptly crashes. I want to be able to pass it an absolute path to the configuration files, which I know will always live alongside the executable. The same goes for debugging in Visual Studio - I\'d like to be able to run $(TargetPath) without having to set the working directory.

回答1:

There is no cross platform way that I know.

For Linux: readlink /proc/self/exe

Windows: GetModuleFileName

回答2:

This way uses boost + argv. You mentioned this may not be cross platform because it may or may not include the executable name. Well the following code should work around that.

#include <boost/filesystem/operations.hpp>

#include <boost/filesystem/path.hpp>

#include <iostream>

namespace fs = boost::filesystem;


int main(int argc,char** argv)
{
    fs::path full_path( fs::initial_path<fs::path>() );

    full_path = fs::system_complete( fs::path( argv[0] ) );

    std::cout << full_path << std::endl;

    //Without file name
    std::cout << full_path.stem() << std::endl;
    //std::cout << fs::basename(full_path) << std::endl;

    return 0;
}

The following code gets the current working directory which may do what you need

#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>

#include <iostream>

namespace fs = boost::filesystem;


int main(int argc,char** argv)
{
    //current working directory
    fs::path full_path( fs::current_path<fs::path>() );

    std::cout << full_path << std::endl;

    std::cout << full_path.stem() << std::endl;
    //std::cout << fs::basepath(full_path) << std::endl;

    return 0;
}

Note Just realized that basename() was deprecated so had to switch to .stem()

回答3:

The boost::dll::program_location function is one of the best cross platform methods of getting the path of the running executable that I know of. The DLL library was added to Boost in version 1.61.0.

The following is my solution. I have tested it on Windows, Mac OS X, Solaris, Free BSD, and GNU/Linux.

It requires Boost 1.55.0 or greater. It uses the Boost.Filesystem library directly and the Boost.Locale library and Boost.System library indirectly.

src/executable_path.cpp

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <iterator>
#include <string>
#include <vector>

#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/predef.h>
#include <boost/version.hpp>
#include <boost/tokenizer.hpp>

#if (BOOST_VERSION > BOOST_VERSION_NUMBER(1,64,0))
#  include <boost/process.hpp>
#endif

#if (BOOST_OS_CYGWIN || BOOST_OS_WINDOWS)
#  include <Windows.h>
#endif

#include <boost/executable_path.hpp>
#include <boost/detail/executable_path_internals.hpp>

namespace boost {

#if (BOOST_OS_CYGWIN || BOOST_OS_WINDOWS)

std::string executable_path(const char* argv0)
{
  typedef std::vector<char> char_vector;
  typedef std::vector<char>::size_type size_type;
  char_vector buf(1024, 0);
  size_type size = buf.size();
  bool havePath = false;
  bool shouldContinue = true;
  do
  {
    DWORD result = GetModuleFileNameA(nullptr, &buf[0], size);
    DWORD lastError = GetLastError();
    if (result == 0)
    {
      shouldContinue = false;
    }
    else if (result < size)
    {
      havePath = true;
      shouldContinue = false;
    }
    else if (
      result == size
      && (lastError == ERROR_INSUFFICIENT_BUFFER || lastError == ERROR_SUCCESS)
      )
    {
      size *= 2;
      buf.resize(size);
    }
    else
    {
      shouldContinue = false;
    }
  } while (shouldContinue);
  if (!havePath)
  {
    return detail::executable_path_fallback(argv0);
  }
  // On Microsoft Windows, there is no need to call boost::filesystem::canonical or
  // boost::filesystem::path::make_preferred. The path returned by GetModuleFileNameA
  // is the one we want.
  std::string ret = &buf[0];
  return ret;
}

#elif (BOOST_OS_MACOS)

#  include <mach-o/dyld.h>

std::string executable_path(const char* argv0)
{
  typedef std::vector<char> char_vector;
  char_vector buf(1024, 0);
  uint32_t size = static_cast<uint32_t>(buf.size());
  bool havePath = false;
  bool shouldContinue = true;
  do
  {
    int result = _NSGetExecutablePath(&buf[0], &size);
    if (result == -1)
    {
      buf.resize(size + 1);
      std::fill(std::begin(buf), std::end(buf), 0);
    }
    else
    {
      shouldContinue = false;
      if (buf.at(0) != 0)
      {
        havePath = true;
      }
    }
  } while (shouldContinue);
  if (!havePath)
  {
    return detail::executable_path_fallback(argv0);
  }
  std::string path(&buf[0], size);
  boost::system::error_code ec;
  boost::filesystem::path p(
    boost::filesystem::canonical(path, boost::filesystem::current_path(), ec));
  if (ec.value() == boost::system::errc::success)
  {
    return p.make_preferred().string();
  }
  return detail::executable_path_fallback(argv0);
}

#elif (BOOST_OS_SOLARIS)

#  include <stdlib.h>

std::string executable_path(const char* argv0)
{
  std::string ret = getexecname();
  if (ret.empty())
  {
    return detail::executable_path_fallback(argv0);
  }
  boost::filesystem::path p(ret);
  if (!p.has_root_directory())
  {
    boost::system::error_code ec;
    p = boost::filesystem::canonical(
      p, boost::filesystem::current_path(), ec);
    if (ec.value() != boost::system::errc::success)
    {
      return detail::executable_path_fallback(argv0);
    }
    ret = p.make_preferred().string();
  }
  return ret;
}

#elif (BOOST_OS_BSD)

#  include <sys/sysctl.h>

std::string executable_path(const char* argv0)
{
  typedef std::vector<char> char_vector;
  int mib[4]{0};
  size_t size;
  mib[0] = CTL_KERN;
  mib[1] = KERN_PROC;
  mib[2] = KERN_PROC_PATHNAME;
  mib[3] = -1;
  int result = sysctl(mib, 4, nullptr, &size, nullptr, 0);
  if (-1 == result)
  {
    return detail::executable_path_fallback(argv0);
  }
  char_vector buf(size + 1, 0);
  result = sysctl(mib, 4, &buf[0], &size, nullptr, 0);
  if (-1 == result)
  {
    return detail::executable_path_fallback(argv0);
  }
  std::string path(&buf[0], size);
  boost::system::error_code ec;
  boost::filesystem::path p(
    boost::filesystem::canonical(
      path, boost::filesystem::current_path(), ec));
  if (ec.value() == boost::system::errc::success)
  {
    return p.make_preferred().string();
  }
  return detail::executable_path_fallback(argv0);
}

#elif (BOOST_OS_LINUX)

#  include <unistd.h>

std::string executable_path(const char *argv0)
{
  typedef std::vector<char> char_vector;
  typedef std::vector<char>::size_type size_type;
  char_vector buf(1024, 0);
  size_type size = buf.size();
  bool havePath = false;
  bool shouldContinue = true;
  do
  {
    ssize_t result = readlink(\"/proc/self/exe\", &buf[0], size);
    if (result < 0)
    {
      shouldContinue = false;
    }
    else if (static_cast<size_type>(result) < size)
    {
      havePath = true;
      shouldContinue = false;
      size = result;
    }
    else
    {
      size *= 2;
      buf.resize(size);
      std::fill(std::begin(buf), std::end(buf), 0);
    }
  } while (shouldContinue);
  if (!havePath)
  {
    return detail::executable_path_fallback(argv0);
  }
  std::string path(&buf[0], size);
  boost::system::error_code ec;
  boost::filesystem::path p(
    boost::filesystem::canonical(
      path, boost::filesystem::current_path(), ec));
  if (ec.value() == boost::system::errc::success)
  {
    return p.make_preferred().string();
  }
  return detail::executable_path_fallback(argv0);
}

#else

std::string executable_path(const char *argv0)
{
  return detail::executable_path_fallback(argv0);
}

#endif

}

src/detail/executable_path_internals.cpp

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <iterator>
#include <string>
#include <vector>

#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/predef.h>
#include <boost/version.hpp>
#include <boost/tokenizer.hpp>

#if (BOOST_VERSION > BOOST_VERSION_NUMBER(1,64,0))
#  include <boost/process.hpp>
#endif

#if (BOOST_OS_CYGWIN || BOOST_OS_WINDOWS)
#  include <Windows.h>
#endif

#include <boost/executable_path.hpp>
#include <boost/detail/executable_path_internals.hpp>

namespace boost {
namespace detail {

std::string GetEnv(const std::string& varName)
{
  if (varName.empty()) return \"\";
#if (BOOST_OS_BSD || BOOST_OS_CYGWIN || BOOST_OS_LINUX || BOOST_OS_MACOS || BOOST_OS_SOLARIS)
  char* value = std::getenv(varName.c_str());
  if (!value) return \"\";
  return value;
#elif (BOOST_OS_WINDOWS)
  typedef std::vector<char> char_vector;
  typedef std::vector<char>::size_type size_type;
  char_vector value(8192, 0);
  size_type size = value.size();
  bool haveValue = false;
  bool shouldContinue = true;
  do
  {
    DWORD result = GetEnvironmentVariableA(varName.c_str(), &value[0], size);
    if (result == 0)
    {
      shouldContinue = false;
    }
    else if (result < size)
    {
      haveValue = true;
      shouldContinue = false;
    }
    else
    {
      size *= 2;
      value.resize(size);
    }
  } while (shouldContinue);
  std::string ret;
  if (haveValue)
  {
    ret = &value[0];
  }
  return ret;
#else
  return \"\";
#endif
}

bool GetDirectoryListFromDelimitedString(
  const std::string& str,
  std::vector<std::string>& dirs)
{
  typedef boost::char_separator<char> char_separator_type;
  typedef boost::tokenizer<
    boost::char_separator<char>, std::string::const_iterator,
    std::string> tokenizer_type;
  dirs.clear();
  if (str.empty())
  {
    return false;
  }
#if (BOOST_OS_WINDOWS)
  const std::string os_pathsep(\";\");
#else
  const std::string os_pathsep(\":\");
#endif
  char_separator_type pathSep(os_pathsep.c_str());
  tokenizer_type strTok(str, pathSep);
  typename tokenizer_type::iterator strIt;
  typename tokenizer_type::iterator strEndIt = strTok.end();
  for (strIt = strTok.begin(); strIt != strEndIt; ++strIt)
  {
    dirs.push_back(*strIt);
  }
  if (dirs.empty())
  {
    return false;
  }
  return true;
}

std::string search_path(const std::string& file)
{
  if (file.empty()) return \"\";
  std::string ret;
#if (BOOST_VERSION > BOOST_VERSION_NUMBER(1,64,0))
  {
    namespace bp = boost::process;
    boost::filesystem::path p = bp::search_path(file);
    ret = p.make_preferred().string();
  }
#endif
  if (!ret.empty()) return ret;
  // Drat! I have to do it the hard way.
  std::string pathEnvVar = GetEnv(\"PATH\");
  if (pathEnvVar.empty()) return \"\";
  std::vector<std::string> pathDirs;
  bool getDirList = GetDirectoryListFromDelimitedString(pathEnvVar, pathDirs);
  if (!getDirList) return \"\";
  std::vector<std::string>::const_iterator it = pathDirs.cbegin();
  std::vector<std::string>::const_iterator itEnd = pathDirs.cend();
  for ( ; it != itEnd; ++it)
  {
    boost::filesystem::path p(*it);
    p /= file;
    if (boost::filesystem::exists(p) && boost::filesystem::is_regular_file(p))
    {
      return p.make_preferred().string();
    }
  }
  return \"\";
}

std::string executable_path_fallback(const char *argv0)
{
  if (argv0 == nullptr) return \"\";
  if (argv0[0] == 0) return \"\";
#if (BOOST_OS_WINDOWS)
  const std::string os_sep(\"\\\\\");
#else
  const std::string os_sep(\"/\");
#endif
  if (strstr(argv0, os_sep.c_str()) != nullptr)
  {
    boost::system::error_code ec;
    boost::filesystem::path p(
      boost::filesystem::canonical(
        argv0, boost::filesystem::current_path(), ec));
    if (ec.value() == boost::system::errc::success)
    {
      return p.make_preferred().string();
    }
  }
  std::string ret = search_path(argv0);
  if (!ret.empty())
  {
    return ret;
  }
  boost::system::error_code ec;
  boost::filesystem::path p(
    boost::filesystem::canonical(
      argv0, boost::filesystem::current_path(), ec));
  if (ec.value() == boost::system::errc::success)
  {
    ret = p.make_preferred().string();
  }
  return ret;
}

}
}

include/boost/executable_path.hpp

#ifndef BOOST_EXECUTABLE_PATH_HPP_
#define BOOST_EXECUTABLE_PATH_HPP_

#pragma once

#include <string>

namespace boost {
std::string executable_path(const char * argv0);
}

#endif // BOOST_EXECUTABLE_PATH_HPP_

include/boost/detail/executable_path_internals.hpp

#ifndef BOOST_DETAIL_EXECUTABLE_PATH_INTERNALS_HPP_
#define BOOST_DETAIL_EXECUTABLE_PATH_INTERNALS_HPP_

#pragma once

#include <string>
#include <vector>

namespace boost {
namespace detail {
std::string GetEnv(const std::string& varName);
bool GetDirectoryListFromDelimitedString(
    const std::string& str,
    std::vector<std::string>& dirs);
std::string search_path(const std::string& file);
std::string executable_path_fallback(const char * argv0);
}
}

#endif // BOOST_DETAIL_EXECUTABLE_PATH_INTERNALS_HPP_

I have a complete project, including a test application and CMake build files available at SnKOpen - /cpp/executable_path/trunk. This version is more complete than the version I provided here. It is also supports more platforms.

I have tested the application on all supported operating systems in the following four scenarios.

1. Relative path, executable in current directory: i.e. ./executable_path_test
2. Relative path, executable in another directory: i.e. ./build/executable_path_test
3. Full path: i.e. /some/dir/executable_path_test
4. Executable in path, file name only: i.e. executable_path_test

In all four scenarios, both the executable_path and executable_path_fallback functions work and return the same results.

Notes

This is an updated answer to this question. I updated the answer to take into consideration user comments and suggestions. I also added a link to a project in my SVN Repository.

回答4:

I\'m not sure about Linux, but try this for Windows:

#include <windows.h>
#include <iostream>

using namespace std ;

int main()
{
     char ownPth[MAX_PATH]; 

     // When NULL is passed to GetModuleHandle, the handle of the exe itself is returned
     HMODULE hModule = GetModuleHandle(NULL);
     if (hModule != NULL)
     {
         // Use GetModuleFileName() with module handle to get the path
         GetModuleFileName(hModule, ownPth, (sizeof(ownPth))); 
         cout << ownPth << endl ;
         system(\"PAUSE\");
         return 0;
     }
     else
     {
         cout << \"Module handle is NULL\" << endl ;
         system(\"PAUSE\");
         return 0;
     }
}

回答5:

For windows:

GetModuleFileName - returns the exe path + exe filename

To remove filename
PathRemoveFileSpec

回答6:

This is a Windows specific way, but it is at least half of your answer.

GetThisPath.h

/// dest is expected to be MAX_PATH in length.
/// returns dest
///     TCHAR dest[MAX_PATH];
///     GetThisPath(dest, MAX_PATH);
TCHAR* GetThisPath(TCHAR* dest, size_t destSize);

GetThisPath.cpp

#include <Shlwapi.h>
#pragma comment(lib, \"shlwapi.lib\")

TCHAR* GetThisPath(TCHAR* dest, size_t destSize)
{
    if (!dest) return NULL;
    if (MAX_PATH > destSize) return NULL;

    DWORD length = GetModuleFileName( NULL, dest, destSize );
    PathRemoveFileSpec(dest);
    return dest;
}

mainProgram.cpp

TCHAR dest[MAX_PATH];
GetThisPath(dest, MAX_PATH);

I would suggest using platform detection as preprocessor directives to change the implementation of a wrapper function that calls GetThisPath for each platform.

回答7:

QT provides this with OS abstraction as QCoreApplication::applicationDirPath()

回答8:

Using args[0] and looking for \'/\' (or \'\\\\\'):

#include <string>
#include <iostream> // to show the result

int main( int numArgs, char *args[])
{
    // Get the last position of \'/\'
    std::string aux(args[0]);

    // get \'/\' or \'\\\\\' depending on unix/mac or windows.
#if defined(_WIN32) || defined(WIN32)
    int pos = aux.rfind(\'\\\\\');
#else
    int pos = aux.rfind(\'/\');
#endif

    // Get the path and the name
    std::string path = aux.substr(0,pos+1);
    std::string name = aux.substr(pos+1);
    // show results
    std::cout << \"Path: \" << path << std::endl;
    std::cout << \"Name: \" << name << std::endl;
}

EDITED: If \'/\' does not exist, pos==-1 so the result is correct.

回答9:

For Windows you can use GetModuleFilename().
For Linux see BinReloc (old, defunct URL) mirror of BinReloc in datenwolf\'s GitHub repositories.

回答10:

The following works as a quick and dirty solution, but note that it is far from being foolproof:

#include <iostream>

using namespace std ;

int main( int argc, char** argv)
{
    cout << argv[0] << endl ;
    return 0;
}

回答11:

Well I have found a very interesting solution for Linux users(tested) and may work for windows as well.

Here is the link

You can create the exe file in linux by typing this in terminal : g++ -o test test.cpp

回答12:

In case you need to handle unicode paths for Windows:

#include <Windows.h>
#include <iostream>

int wmain(int argc, wchar_t * argv[])
{
    HMODULE this_process_handle = GetModuleHandle(NULL);
    wchar_t this_process_path[MAX_PATH];

    GetModuleFileNameW(NULL, this_process_path, sizeof(this_process_path));

    std::wcout << \"Unicode path of this app: \" << this_process_path << std::endl;

    return 0;
}

回答13:

For Windows, you have the problem of how to strip the executable from the result of GetModuleFileName(). The Windows API call PathRemoveFileSpec() that Nate used for that purpose in his answer changed between Windows 8 and its predecessors. So how to remain compatible with both and safe? Luckily, there\'s C++17 (or Boost, if you\'re using an older compiler). I do this:

#include <windows.h>
#include <string>
#include <filesystem>
namespace fs = std::experimental::filesystem;

// We could use fs::path as return type, but if you\'re not aware of
// std::experimental::filesystem, you probably handle filenames
// as strings anyway in the remainder of your code.  I\'m on Japanese
// Windows, so wide chars are a must.
std::wstring getDirectoryWithCurrentExecutable()
{
    int size = 256;
    std::vector<wchar_t> charBuffer;
    // Let\'s be safe, and find the right buffer size programmatically.
    do {
        size *= 2;
        charBuffer.resize(size);
        // Resize until filename fits.  GetModuleFileNameW returns the
        // number of characters written to the buffer, so if the
        // return value is smaller than the size of the buffer, it was
        // large enough.
    } while (GetModuleFileNameW(NULL, charBuffer.data(), size) == size);
    // Typically: c:/program files (x86)/something/foo/bar/exe/files/win64/baz.exe
    // (Note that windows supports forward and backward slashes as path
    // separators, so you have to be careful when searching through a path
    // manually.)

    // Let\'s extract the interesting part:
    fs::path path(charBuffer.data());  // Contains the full path including .exe
    return path.remove_filename()  // Extract the directory ...
               .w_str();           // ... and convert to a string.
}

回答14:

This was my solution in Windows. It is called like this:

std::wstring sResult = GetPathOfEXE(64);

Where 64 is the minimum size you think the path will be. GetPathOfEXE calls itself recursively, doubling the size of the buffer each time until it gets a big enough buffer to get the whole path without truncation.

std::wstring GetPathOfEXE(DWORD dwSize)
{
    WCHAR* pwcharFileNamePath;
    DWORD dwLastError;
    HRESULT hrError;
    std::wstring wsResult;
    DWORD dwCount;

    pwcharFileNamePath = new WCHAR[dwSize];

    dwCount = GetModuleFileNameW(
        NULL,
        pwcharFileNamePath,
        dwSize
    );

    dwLastError = GetLastError();

    if (ERROR_SUCCESS == dwLastError)
    {
        hrError = PathCchRemoveFileSpec(
            pwcharFileNamePath,
            dwCount
        );

        if (S_OK == hrError)
        {
            wsResult = pwcharFileNamePath;

            if (pwcharFileNamePath)
            {
                delete pwcharFileNamePath;
            }

            return wsResult;
        }
        else if(S_FALSE == hrError)
        {
            wsResult = pwcharFileNamePath;

            if (pwcharFileNamePath)
            {
                delete pwcharFileNamePath;
            }

            //there was nothing to truncate off the end of the path
            //returning something better than nothing in this case for the user
            return wsResult;
        }
        else
        {
            if (pwcharFileNamePath)
            {
                delete pwcharFileNamePath;
            }

            std::ostringstream oss;
            oss << \"could not get file name and path of executing process. error truncating file name off path. last error : \" << hrError;
            throw std::runtime_error(oss.str().c_str());
        }
    }
    else if (ERROR_INSUFFICIENT_BUFFER == dwLastError)
    {
        if (pwcharFileNamePath)
        {
            delete pwcharFileNamePath;
        }

        return GetPathOfEXE(
            dwSize * 2
        );
    }
    else
    {
        if (pwcharFileNamePath)
        {
            delete pwcharFileNamePath;
        }

        std::ostringstream oss;
        oss << \"could not get file name and path of executing process. last error : \" << dwLastError;
        throw std::runtime_error(oss.str().c_str());
    }
}

回答15:

char exePath[512];
CString strexePath;
GetModuleFileName(NULL,exePath,512);
strexePath.Format(\"%s\",exePath);
strexePath = strexePath.Mid(0,strexePath.ReverseFind(\'\\\\\'));

回答16:

This method works for both Windows and Linux:

#include <stdio.h>
#include <string>
#ifdef _WIN32
#include <direct.h>
#define GetCurrentDir _getcwd
#elif __linux__
#include <unistd.h>
#define GetCurrentDir getcwd
#endif

std::string GetCurrentWorkingDir() 
{
    char buff[FILENAME_MAX];
    GetCurrentDir(buff, FILENAME_MAX);
    std::string current_working_dir(buff);
    return current_working_dir;
}

回答17:

in Unix(including Linux) try \'which\', in Windows try \'where\'.

#include <stdio.h>

#define _UNIX

int main(int argc, char** argv)
{
        char cmd[128];
        char buf[128];
        FILE* fp = NULL;
#if defined(_UNIX)
        sprintf(cmd, \"which %s > my.path\", argv[0]);
#else
        sprintf(cmd, \"where %s > my.path\", argv[0]);
#endif
        system(cmd);
        fp = fopen(\"my.path\", \"r\");
        fgets(buf, sizeof(buf), fp);
        fclose(fp);

        printf(\"full path: %s\\n\", buf);
        unlink(\"my.path\");

        return 0;
}