How do I get the directory that a program is running from

Question

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

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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

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Path to the current  exe   include  lt Windows h gt   std  wstring getexepathW         wchar t result MAX PATH       return std  wstring result  GetModuleFileNameW NULL  result  MAX PATH       std  wcout  lt  lt  getexepathW    lt  lt  std  endl       -------- OR --------  std  string getexepathA         char result MAX PATH       return std  string result  GetModuleFileNameA NULL  result  MAX PATH       std  cout  lt  lt  getexepathA    lt  lt  std  endl

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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  lt filesystem gt   else  include  lt experimental filesystem gt   namespace std       namespace filesystem   experimental  filesystem     endif  std  filesystem  path getexepath      application cpp    include  application h   ifdef  WIN32  include  lt windows h gt       GetModuleFileNameW  else  include  lt limits h gt   include  lt unistd h gt        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  gt  0    count   0    endif

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Here s code to get the full path to the executing app  Windows  char pBuf 256   size t len   sizeof pBuf    int bytes   GetModuleFileName NULL  pBuf  len   return bytes   bytes   -1   Linux  int bytes   MIN readlink  quot  proc self exe quot   pBuf  len   len - 1   if bytes  gt   0      pBuf bytes      0   return bytes

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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

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Use realpath   in stdlib h like this   char  working dir path   realpath      NULL

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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

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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

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A library solution  although I know this was not asked for   If you happen to use Qt  QCoreApplication  applicationDirPath

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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

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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  lt experimental filesystem gt    and link your code with -lstdc  fs flag   If you want to use Filesystem with Microsoft Visual Studio  then read this

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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   ---- gt  test   ---- gt  src   ---- gt  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

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Just my two cents  but doesn t the following code portably work in C  17    include  lt iostream gt   include  lt filesystem gt  namespace fs   std  filesystem   int main int argc  char  argv          std  cout  lt  lt   Path is    lt  lt  fs  path argv 0   parent path    lt  lt    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 amp  filename  const std  string amp  exe path          With implementation   fs  path prepend exe path const std  string amp  filename  const std  string amp  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

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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  lt stdio h gt   include  lt unistd h gt   include  lt string h gt   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

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For Win32 GetCurrentDirectory should do the trick

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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

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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  lt stdio h gt      defines FILENAME MAX     ifdef WINDOWS      include  lt direct h gt       define GetCurrentDir  getcwd  else      include  lt unistd h gt       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

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include  lt windows h gt  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

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Here s code to get the full path to the executing app  Windows  char pBuf 256   size t len   sizeof pBuf    int bytes   GetModuleFileName NULL  pBuf  len   return bytes   bytes   -1   Linux  int bytes   MIN readlink  quot  proc self exe quot   pBuf  len   len - 1   if bytes  gt   0      pBuf bytes      0   return bytes

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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

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This is from the cplusplus forum  On windows    include  lt string gt   include  lt windows h gt   std  string getexepath       char result  MAX PATH      return std  string  result  GetModuleFileName  NULL  result  MAX PATH          On Linux    include  lt string gt   include  lt limits h gt   include  lt unistd h gt   std  string getexepath       char result  PATH MAX      ssize t count   readlink    proc self exe   result  PATH MAX      return std  string  result   count  gt  0    count   0        On HP-UX    include  lt string gt   include  lt limits h gt   define  PSTAT64  include  lt sys pstat h gt   include  lt sys types h gt   include  lt unistd h gt   std  string getexepath       char result  PATH MAX      struct pst status ps     if  pstat getproc   amp ps  sizeof  ps    0  getpid      lt  0      return std  string       if  pstat getpathname  result  PATH MAX   amp ps pst fid text    lt  0      return std  string       return std  string  result

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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

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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

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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

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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  amp path   printf path      Example output  C  Projects Hello World exe

[c++] How do I get the directory that a program is running from?

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