I’m writing a ‘C’ program that makes several calls to system() to execute other programs. When constructing the command string is it better to explicitly give the full path to the program being called, or should I just give the executable name and let the shell resolve its location using the PATH environment variable?
The programs I’m calling are all part of a single package and I have the path to the installation directory from a preprocessor definition. Giving the explicit path would seem to avoid errors that might occur if multiple installed programs share the same name. However it makes building the command strings a little more complicated, and everything will break if the user moves the programs around after installation.
Is there a widely accepted best practice covering this?
[Clarification]
I’m using autoconf/automake to generate the distribuion. The preprocessor definition providing the installation directory is created by the makefile. It reflects the user’s choice of the installation directory as specified either on the configure comamnd line or the make command line. I do take the point about using environment variables to specify the location for the binaries though. It seems like an unneeded pain in the butt to make users rebuild just to change the location of the binaries.
The best practice is to not presume anything about the system you’re installing onto. You can have the best of both worlds if you just let the user choose. Make the command you call an application preference or require paths to be defined in the environment:
You can, of course, just fall back to a default of some kind if the variables aren’t defined or the preference isn’t set. Writing your application to be more flexible is always the best choice!