How to get executable's full path using C/C++?

oldbee · 02-18-2002, 10:10 AM

Hi, I think this question might be typical!

I have an execuatable that could be moved around in my file sys tree. I need to find out - in my C++ exe code - which dir the exe is.

I know I could use dirname/which in shell and env var passed into c code. I think they work most of the time when symbolic link is not invoved. I prefer a function in c that could tell me where the execuatble is located.

Any experience?

Thanks!

- oldbee

Malicious · 02-18-2002, 04:08 PM

Well, argv[0] contains the path that was used to run the program and getcwd() will get you the path of the current working directory which will be where the program was executed from. By munging the two together you should be able to come up with something. If the first character of argv[0] is "/", then that is the path name of the program. If it is not, then append argv[0] to the path returned from getcwd() and voila, FM. There could be some "../../" in this but it will still be a vaild path.

If the executeable was found with the PATH environment variable, the above won't find it and you will have to spin all of the paths in PATH and check each one to see if the file is there.

Out of curiosity, does the program do something based on its location in the tree?

oldbee · 02-18-2002, 04:15 PM

To answer Malicious's question, my program does rely on where the executable is for the following info:
where the shared lib is;
where the some resource files located;

Also, I do need to think about the sym link and PATH cases.

Thanks for your answser!

oldbee

Malicious · 02-18-2002, 04:51 PM

Another pure Linux way to do this is to use the /proc file system. /proc/<pid>/exe is a symbolic link to the executeable for that pid.

oldbee · 02-18-2002, 05:00 PM

Malicious,

Good to know that!
I probably go with the script method because I only know my pid after my shared lib is resolved, also for portability(other unix) reason I will not use /proc.

Thank you much thou.

oldbee

crabboy · 02-18-2002, 10:06 PM

This should work.

Code:

#include <stdio.h>
#include <unistd.h>

main()
{
   printf("%s\n", get_current_dir_name());
}

oldbee · 02-19-2002, 09:21 AM

crabboy, PWD is not what I want thou. Thanks anyway.