Can I safely assume that Windows Explorer is always started from a Windows system directory? Also, is its process always named "explorer.exe"?
And if not, how to get its full file path?
EDIT: Forgot to mention -- I need this to later find out the process ID of the Windows Explorer running in a given user session. Thus my search for its full path.
EDIT 2: Thanks everyone who contributed, and especially to sehe! After his post I found this page that explains how to set up your own shell. I made a wild test by completely replacing explorer.exe with my own process and here's the result:
Here's the full-size link if you it gets re-sized.
As you can see, I can technically replace explorer.exe with whatever process I may come up with. As you can also see in my screenshot Windows gives me a complete control over the Shell (the screenshot is my entire window.)
So the bottom line, the only way to get "explorer.exe" file path (or whatever Shell process is used) is to use those registry keys from the link I quoted above -- pretty much close to what sehe suggested, with just a few more checks to do, but it's a pretty straightforward stuff.
As for Sean Cline's suggestion, it would be a very elegant solution ONLY if we have the "stock" Windows Explorer running that comes with a tray window with that specific class name.
It is probably safe to assume that explorer.exe is always in the %windir% or %SystemRoot% as it hasn't moved for years. But, if you are trying to invoke something via Explorer, chances are you want to use the ShellExecute() function instead.
If you really do need the path, the easiest way to get it is probably with a call to SHGetKnownFolderPath() using FOLDERID_Windows as the first argument.
Edit:
Here is my stab at some code knowing that you are looking for the PID of the shell process:
DWORD trayPID;
HWND trayWnd = FindWindow("Shell_TrayWnd", NULL);
GetWindowThreadProcessId(trayWnd, &trayPID);
It looks for the hWnd of the taskbar and finds the owning PID. You will likely need to add some error handling for the case that explorer is not running and that window does not exist - unlikely, but possible.
No you can't safely assume that and none of this has to do with C++.
Also, you didn't show any code. Here goes:
The registry key for this is Software\Microsoft\Windows NT\CurrentVersion\WinLogon\Shell (see here).
#include <windows.h>
#include <malloc.h>
#include <stdio.h>
#include <string>
LONG GetStringRegKey(HKEY hKey, const std::wstring &strValueName, std::wstring &strValue, const std::wstring &strDefaultValue)
{
strValue = strDefaultValue;
WCHAR szBuffer[512];
DWORD dwBufferSize = sizeof(szBuffer);
ULONG nError;
nError = RegQueryValueExW(hKey, strValueName.c_str(), 0, NULL, (LPBYTE)szBuffer, &dwBufferSize);
if (ERROR_SUCCESS == nError)
{
strValue = szBuffer;
}
return nError;
}
int main()
{
HKEY hKey;
LONG lRes = RegOpenKeyExW(HKEY_LOCAL_MACHINE, L"Software\\Microsoft\\Windows NT\\CurrentVersion\\WinLogon", 0, KEY_READ, &hKey);
bool bExistsAndSuccess (lRes == ERROR_SUCCESS);
bool bDoesNotExistsSpecifically (lRes == ERROR_FILE_NOT_FOUND);
std::wstring shell;
GetStringRegKey(hKey, L"Shell", shell, L"");
}
Yes to both. Windows Explorer is always located at %WINDIR%\Explorer.exe.
I am trying to hard code into C++ program to look for config.ini in the same directory as the executable, without knowing the complete path to the file. I am trying to find a way to make a local reference to the executable.
Basically load ("./config.ini")
without doing
("C:\foo\bar\config.ini")
There isn't really any guaranteed portable way of doing this, but I like to use this code because it works in the vast majority of cases (unless symlinks or other magic is involved):
boost::filesystem::current_path(boost::filesystem::path(argv[0]).remove_filename());
If you are willing to use platform specific code look at GetModuleFileName on Windows and a mix of getpid, reading from /proc and readlink on Linux.
You want GetModuleFilename() on Windows (pass NULL to get filename of current executable). Otherwise, call boost::filesystem::initial_path() early in the program (see Boost docs in link for the reason to do this early). That should cover most of the situations.
Edit
Brain malfunction. We always start our programs from the executable's directory, so the boost::initial_path() thing works, but it won't work so well if you start the program from another direcory. Sorry for the confusion on that. On Windows, though, I'd get the path from GetModuleFilename and use boost::path to manipulate the result.
For windows, this will get the directory containing the excutable as a c++ string:
#include <windows.h>
#include <string>
#include <iostream>
using namespace std;;
string ExePath() {
char buffer[MAX_PATH];
GetModuleFileName( NULL, buffer, MAX_PATH );
string::size_type pos = string( buffer ).find_last_of( "\\/" );
return string( buffer ).substr( 0, pos);
}
You can then just tag the name of your config file on the end.
For Windows:
#include <direct.h>
char cur_path[FILENAME_MAX];
if (!_getcwd(cur_path, sizeof(cur_path)))
{
// deal with error
}
cur_path[sizeof(cur_path) - 1] = '/0'; // adding \0 at the end of the string
printf("Current dir: %s", cur_path);
A platform-agnostic solution was discussed here:
How do I get the directory that a program is running from?
I looked all over the internet and there doesn't seem to be a decent solution that I could find. I want to be able to programmatically in C++ obtain the path "%ALLUSERSPROFILE%\Application Data" that explorer can translate into a real path.
Can I do this without relying on third-party code?
Use SHGetFolderPath with CSIDL_COMMON_APPDATA as the CSIDL.
TCHAR szPath[MAX_PATH];
if (SUCCEEDED(SHGetFolderPath(NULL, CSIDL_COMMON_APPDATA, NULL, 0, szPath)))
{
//....
}
Just to suppliment interjay's answer
I had to include shlobj.h to use SHGetFolderPath.
Often you may need to read a file from appdata,
to do this you need to use the pathAppend function (shlwapi.h is needed for this).
#include <shlwapi.h>
#pragma comment(lib,"shlwapi.lib")
#include "shlobj.h"
TCHAR szPath[MAX_PATH];
// Get path for each computer, non-user specific and non-roaming data.
if ( SUCCEEDED( SHGetFolderPath( NULL, CSIDL_COMMON_APPDATA, NULL, 0, szPath ) ) )
{
// Append product-specific path
PathAppend( szPath, _T("\\My Company\\My Product\\1.0\\") );
}
See here for more details.
you can also read the value from the registry
path = HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
key = Common AppData
Is there a platform-agnostic and filesystem-agnostic method to obtain the full path of the directory from where a program is running using C/C++? Not to be confused with the current working directory. (Please don't suggest libraries unless they're standard ones like clib or STL.)
(If there's no platform/filesystem-agnostic method, suggestions that work in Windows and Linux for specific filesystems are welcome too.)
Here's code to get the full path to the executing app:
Variable declarations:
char pBuf[256];
size_t len = sizeof(pBuf);
Windows:
int bytes = GetModuleFileName(NULL, pBuf, len);
return bytes ? bytes : -1;
Linux:
int bytes = MIN(readlink("/proc/self/exe", pBuf, len), len - 1);
if(bytes >= 0)
pBuf[bytes] = '\0';
return bytes;
If you fetch the current directory when your program first starts, then you effectively have the directory your program was started from. Store the value in a variable and refer to it later in your program. This is distinct from the directory that holds the current executable program file. It isn't necessarily the same directory; if someone runs the program from a command prompt, then the program is being run from the command prompt's current working directory even though the program file lives elsewhere.
getcwd is a POSIX function and supported out of the box by all POSIX compliant platforms. You would not have to do anything special (apart from incliding the right headers unistd.h on Unix and direct.h on windows).
Since you are creating a C program it will link with the default c run time library which is linked to by ALL processes in the system (specially crafted exceptions avoided) and it will include this function by default. The CRT is never considered an external library because that provides the basic standard compliant interface to the OS.
On windows getcwd function has been deprecated in favour of _getcwd. I think you could use it in this fashion.
#include <stdio.h> /* defines FILENAME_MAX */
#ifdef WINDOWS
#include <direct.h>
#define GetCurrentDir _getcwd
#else
#include <unistd.h>
#define GetCurrentDir getcwd
#endif
char cCurrentPath[FILENAME_MAX];
if (!GetCurrentDir(cCurrentPath, sizeof(cCurrentPath)))
{
return errno;
}
cCurrentPath[sizeof(cCurrentPath) - 1] = '\0'; /* not really required */
printf ("The current working directory is %s", cCurrentPath);
This is from the cplusplus forum
On windows:
#include <string>
#include <windows.h>
std::string getexepath()
{
char result[ MAX_PATH ];
return std::string( result, GetModuleFileName( NULL, result, MAX_PATH ) );
}
On Linux:
#include <string>
#include <limits.h>
#include <unistd.h>
std::string getexepath()
{
char result[ PATH_MAX ];
ssize_t count = readlink( "/proc/self/exe", result, PATH_MAX );
return std::string( result, (count > 0) ? count : 0 );
}
On HP-UX:
#include <string>
#include <limits.h>
#define _PSTAT64
#include <sys/pstat.h>
#include <sys/types.h>
#include <unistd.h>
std::string getexepath()
{
char result[ PATH_MAX ];
struct pst_status ps;
if (pstat_getproc( &ps, sizeof( ps ), 0, getpid() ) < 0)
return std::string();
if (pstat_getpathname( result, PATH_MAX, &ps.pst_fid_text ) < 0)
return std::string();
return std::string( result );
}
If you want a standard way without libraries: No. The whole concept of a directory is not included in the standard.
If you agree that some (portable) dependency on a near-standard lib is okay: Use Boost's filesystem library and ask for the initial_path().
IMHO that's as close as you can get, with good karma (Boost is a well-established high quality set of libraries)
I know it is very late at the day to throw an answer at this one but I found that none of the answers were as useful to me as my own solution. A very simple way to get the path from your CWD to your bin folder is like this:
int main(int argc, char* argv[])
{
std::string argv_str(argv[0]);
std::string base = argv_str.substr(0, argv_str.find_last_of("/"));
}
You can now just use this as a base for your relative path. So for example I have this directory structure:
main
----> test
----> src
----> bin
and I want to compile my source code to bin and write a log to test I can just add this line to my code.
std::string pathToWrite = base + "/../test/test.log";
I have tried this approach on Linux using full path, alias etc. and it works just fine.
NOTE:
If you are on windows you should use a '\' as the file separator not '/'. You will have to escape this too for example:
std::string base = argv[0].substr(0, argv[0].find_last_of("\\"));
I think this should work but haven't tested, so comment would be appreciated if it works or a fix if not.
Filesystem TS is now a standard ( and supported by gcc 5.3+ and clang 3.9+ ), so you can use current_path() function from it:
std::string path = std::experimental::filesystem::current_path();
In gcc (5.3+) to include Filesystem you need to use:
#include <experimental/filesystem>
and link your code with -lstdc++fs flag.
If you want to use Filesystem with Microsoft Visual Studio, then read this.
No, there's no standard way. I believe that the C/C++ standards don't even consider the existence of directories (or other file system organizations).
On Windows the GetModuleFileName() will return the full path to the executable file of the current process when the hModule parameter is set to NULL. I can't help with Linux.
Also you should clarify whether you want the current directory or the directory that the program image/executable resides. As it stands your question is a little ambiguous on this point.
On Windows the simplest way is to use the _get_pgmptr function in stdlib.h to get a pointer to a string which represents the absolute path to the executable, including the executables name.
char* path;
_get_pgmptr(&path);
printf(path); // Example output: C:/Projects/Hello/World.exe
Maybe concatenate the current working directory with argv[0]? I'm not sure if that would work in Windows but it works in linux.
For example:
#include <stdio.h>
#include <unistd.h>
#include <string.h>
int main(int argc, char **argv) {
char the_path[256];
getcwd(the_path, 255);
strcat(the_path, "/");
strcat(the_path, argv[0]);
printf("%s\n", the_path);
return 0;
}
When run, it outputs:
jeremy#jeremy-desktop:~/Desktop$ ./test
/home/jeremy/Desktop/./test
For Win32 GetCurrentDirectory should do the trick.
You can not use argv[0] for that purpose, usually it does contain full path to the executable, but not nessesarily - process could be created with arbitrary value in the field.
Also mind you, the current directory and the directory with the executable are two different things, so getcwd() won't help you either.
On Windows use GetModuleFileName(), on Linux read /dev/proc/procID/.. files.
Just my two cents, but doesn't the following code portably work in C++17?
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main(int argc, char* argv[])
{
std::cout << "Path is " << fs::path(argv[0]).parent_path() << '\n';
}
Seems to work for me on Linux at least.
Based on the previous idea, I now have:
std::filesystem::path prepend_exe_path(const std::string& filename, const std::string& exe_path = "");
With implementation:
fs::path prepend_exe_path(const std::string& filename, const std::string& exe_path)
{
static auto exe_parent_path = fs::path(exe_path).parent_path();
return exe_parent_path / filename;
}
And initialization trick in main():
(void) prepend_exe_path("", argv[0]);
Thanks #Sam Redway for the argv[0] idea. And of course, I understand that C++17 was not around for many years when the OP asked the question.
Just to belatedly pile on here,...
there is no standard solution, because the languages are agnostic of underlying file systems, so as others have said, the concept of a directory based file system is outside the scope of the c / c++ languages.
on top of that, you want not the current working directory, but the directory the program is running in, which must take into account how the program got to where it is - ie was it spawned as a new process via a fork, etc. To get the directory a program is running in, as the solutions have demonstrated, requires that you get that information from the process control structures of the operating system in question, which is the only authority on this question. Thus, by definition, its an OS specific solution.
#include <windows.h>
using namespace std;
// The directory path returned by native GetCurrentDirectory() no end backslash
string getCurrentDirectoryOnWindows()
{
const unsigned long maxDir = 260;
char currentDir[maxDir];
GetCurrentDirectory(maxDir, currentDir);
return string(currentDir);
}
For Windows system at console you can use system(dir) command. And console gives you information about directory and etc. Read about the dir command at cmd. But for Unix-like systems, I don't know... If this command is run, read bash command. ls does not display directory...
Example:
int main()
{
system("dir");
system("pause"); //this wait for Enter-key-press;
return 0;
}
Works with starting from C++11, using experimental filesystem, and C++14-C++17 as well using official filesystem.
application.h:
#pragma once
//
// https://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros
//
#ifdef __cpp_lib_filesystem
#include <filesystem>
#else
#include <experimental/filesystem>
namespace std {
namespace filesystem = experimental::filesystem;
}
#endif
std::filesystem::path getexepath();
application.cpp:
#include "application.h"
#ifdef _WIN32
#include <windows.h> //GetModuleFileNameW
#else
#include <limits.h>
#include <unistd.h> //readlink
#endif
std::filesystem::path getexepath()
{
#ifdef _WIN32
wchar_t path[MAX_PATH] = { 0 };
GetModuleFileNameW(NULL, path, MAX_PATH);
return path;
#else
char result[PATH_MAX];
ssize_t count = readlink("/proc/self/exe", result, PATH_MAX);
return std::string(result, (count > 0) ? count : 0);
#endif
}
For relative paths, here's what I did. I am aware of the age of this question, I simply want to contribute a simpler answer that works in the majority of cases:
Say you have a path like this:
"path/to/file/folder"
For some reason, Linux-built executables made in eclipse work fine with this. However, windows gets very confused if given a path like this to work with!
As stated above there are several ways to get the current path to the executable, but the easiest way I find works a charm in the majority of cases is appending this to the FRONT of your path:
"./path/to/file/folder"
Just adding "./" should get you sorted! :) Then you can start loading from whatever directory you wish, so long as it is with the executable itself.
EDIT: This won't work if you try to launch the executable from code::blocks if that's the development environment being used, as for some reason, code::blocks doesn't load stuff right... :D
EDIT2: Some new things I have found is that if you specify a static path like this one in your code (Assuming Example.data is something you need to load):
"resources/Example.data"
If you then launch your app from the actual directory (or in Windows, you make a shortcut, and set the working dir to your app dir) then it will work like that.
Keep this in mind when debugging issues related to missing resource/file paths. (Especially in IDEs that set the wrong working dir when launching a build exe from the IDE)
A library solution (although I know this was not asked for).
If you happen to use Qt:
QCoreApplication::applicationDirPath()
Path to the current .exe
#include <Windows.h>
std::wstring getexepathW()
{
wchar_t result[MAX_PATH];
return std::wstring(result, GetModuleFileNameW(NULL, result, MAX_PATH));
}
std::wcout << getexepathW() << std::endl;
// -------- OR --------
std::string getexepathA()
{
char result[MAX_PATH];
return std::string(result, GetModuleFileNameA(NULL, result, MAX_PATH));
}
std::cout << getexepathA() << std::endl;
This question was asked 15 years ago, so the existing answers are now incorrect. If you're using C++17 or greater, the solution is very straightforward today:
#include <filesystem>
std::cout << std::filesystem::current_path();
See cppreference.com for more information.
On POSIX platforms, you can use getcwd().
On Windows, you may use _getcwd(), as use of getcwd() has been deprecated.
For standard libraries, if Boost were standard enough for you, I would have suggested Boost::filesystem, but they seem to have removed path normalization from the proposal. You may have to wait until TR2 becomes readily available for a fully standard solution.
Boost Filesystem's initial_path() behaves like POSIX's getcwd(), and neither does what you want by itself, but appending argv[0] to either of them should do it.
You may note that the result is not always pretty--you may get things like /foo/bar/../../baz/a.out or /foo/bar//baz/a.out, but I believe that it always results in a valid path which names the executable (note that consecutive slashes in a path are collapsed to one).
I previously wrote a solution using envp (the third argument to main() which worked on Linux but didn't seem workable on Windows, so I'm essentially recommending the same solution as someone else did previously, but with the additional explanation of why it is actually correct even if the results are not pretty.
As Minok mentioned, there is no such functionality specified ini C standard or C++ standard. This is considered to be purely OS-specific feature and it is specified in POSIX standard, for example.
Thorsten79 has given good suggestion, it is Boost.Filesystem library. However, it may be inconvenient in case you don't want to have any link-time dependencies in binary form for your program.
A good alternative I would recommend is collection of 100% headers-only STLSoft C++ Libraries Matthew Wilson (author of must-read books about C++). There is portable facade PlatformSTL gives access to system-specific API: WinSTL for Windows and UnixSTL on Unix, so it is portable solution. All the system-specific elements are specified with use of traits and policies, so it is extensible framework. There is filesystem library provided, of course.
The linux bash command
which progname will report a path to program.
Even if one could issue the which command from within your program and direct the output to a tmp file and the program
subsequently reads that tmp file, it will not tell you if that program is the one executing. It only tells you where a program having that name is located.
What is required is to obtain your process id number, and to parse out the path to the name
In my program I want to know if the program was
executed from the user's bin directory or from another in the path
or from /usr/bin. /usr/bin would contain the supported version.
My feeling is that in Linux there is the one solution that is portable.
Use realpath() in stdlib.h like this:
char *working_dir_path = realpath(".", NULL);
The following worked well for me on macOS 10.15.7
brew install boost
main.cpp
#include <iostream>
#include <boost/filesystem.hpp>
int main(int argc, char* argv[]){
boost::filesystem::path p{argv[0]};
p = absolute(p).parent_path();
std::cout << p << std::endl;
return 0;
}
Compiling
g++ -Wall -std=c++11 -l boost_filesystem main.cpp