"cd" command from C language

sang_froid · 02-24-2007, 06:29 PM

Hi,
How do I execute cd command from C language ? Execvp is not helping me out. Other commands are running fine from execvp, but some of the commands like cd are not working.

Any suggestions ??

tuxdev · 02-24-2007, 06:41 PM

man chdir

The current directory is a part of the enviroment of a process. A child process cannot mess with its parent's enviroment, so the cd done in the child is lost.

What are you trying to do, anyway? execvp() and friends aren't used that much in programs.

sang_froid · 02-24-2007, 07:05 PM

well that is a part of our assignment, we need to simulate a shell from where i can run commands...

that is what i am confused with, if i do cd and then move on to other directories, how will the process keep on continuing ?

tuxdev · 02-24-2007, 07:20 PM

That's because the child process has its own idea of what is its current directory. It won't change because the parent process changes its current directory. The current directory of a process is in its enviroment, and the enviroments of a parent and child are distinct and independent. The cd command *must* be a shell builtin. In fact, there usually isn't even a cd binary on the system, so you shouldn't even be able to use execvp to run cd.