General :: Error Checking On System Calls

I'm new to C language and some help finding places in the following code where a system call is made and error checking is not done. I found one but since I don't know C language at all I'm not exactly sure what else to look for. Link to my file: [URL]...

I found one and added error checking:
if (setoutpipe){
//Changes: Added error checking to the system call close()
//Orginal Code: close(pidefd[1]);
if(close(pipefd[1] != 0){
fprintf(stderr, "Could not close piple.
");
exit(255);
}