I’m virtually certain this is what you’re trying to do. Apologies in advance for the sloppy coding. its somewhat late here and I really should be sleeping right now: #include <iostream> #include <string> #include <cstdlib> #include <cstdio> #include <unistd.h> #define READ 0 #define WRITE 1 // ps -A | grep argv[1] | wc -l int … Read more
You need to close all the pipe descriptors in both the parent process and the child process (after duplication in the child process). In your code the main issue is that, the wc process does not exit because there are still writers present (since the parent process has not closed the write end). Changes shown … Read more
Even after the first command of your pipeline exits (and thust closes stdout=~fdPipe[1]), the parent still has fdPipe[1] open. Thus, the second command of the pipeline has a stdin=~fdPipe[0] that never gets an EOF, because the other endpoint of the pipe is still open. You need to create a new pipe(fdPipe) for each |, and … Read more
I’d suggest writing your own function to do the piping/forking/system-ing for you. You could have the function spawn a process and return read/write file descriptors, as in… typedef void pfunc_t (int rfd, int wfd); pid_t pcreate(int fds[2], pfunc_t pfunc) { /* Spawn a process from pfunc, returning it’s pid. The fds array passed will * … Read more