An empty directory name is treated as a single dot. This list is subject to change. It removes a variable named s , if one exists. It then adds a variable named s with value t , if the pointer t is nonzero. If it is unable to allocate memory, it returns 0, leaving the pathexec environment alone.
Compatibility notes pathexec is intended as a replacement for execvp .
It is also intended as a replacement for setenv , putenv , and unsetenv in programs that are merely setting up a post-exec environment.