test9_10.txt

Linux下的C语言编程

#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>

int system(const char *cmdstring)
{
	pid_t pid;
	int status;

	if(!cmdstring)
		return(1);
	if((pid=fork())<0)
	status=-1;
	else if(pid==0)
	{
		execl("/bin/sh", "sh", "-c",cmdstring, NULL);
		_exit(255);
	}
	else
	{
		while(waitpid(pid, &status, 0)<0)
		if(errno!=EINTR)
		{
			status=-1;
				break;
		}
	}
	return(status);
}