Locating a program in a portable way

[moseley]

This is more of a programming question, so please let me know if there's 
a better place to ask.

Our project (Swish-e) runs external programs via popen() and system(). 
Some of the external programs are placed in our $libexecdir which is
not normally in the $PATH.

We initially used setenv() to add our $libexecdir to $PATH, but setenv()
doesn't seem to be portable (not sure it exists on Windows, for
example).

So the current plan is to read $PATH, prepend (or append) our 
$libexecdir to the path, and then walk the path looking for the program.  

The problem is how to do it in a portable way.  I'll probably use the 
GNU Which(1) source as a base, but I'm wondering if anyone here has or 
knows of code to do this in a portable way.  I expect VMS and Windows 
will give us the most trouble.

Any pointers?

Thanks,


-- 
Bill Moseley
address@hidden