#include	<sys/wait.h>#include	<errno.h>#include	<unistd.h>intsystem(const char *cmdstring)	/* version without signal handling */{	pid_t	pid;	int		status;	if (cmdstring == NULL)		return(1);		/* always a command processor with UNIX */	if ((pid = fork()) < 0) {		status = -1;	/* probably out of processes */	} else if (pid == 0) {				/* child */		execl("/bin/sh", "sh", "-c", cmdstring, (char *)0);		_exit(127);		/* execl error */	} else {							/* parent */		while (waitpid(pid, &status, 0) < 0) {			if (errno != EINTR) {				status = -1; /* error other than EINTR from waitpid() */				break;			}		}	}	return(status);}