#include??
#include?
#include?

int?main（int?argc?char?**argv）
{
	int?pidfd1fd2;
	sem_id?sem1sem2;
	sem1=create_sem（1“piperun“）;
	sem2=create_sem（1“piperun“）;
	if?（sem1		perror（“create_sem“）;
		exit（1）;
	}
	acquire_sem（sem1）;
	acquire_sem（sem2）;
	pid=fork（）;
	if?（pid==0）?{
		fd1=open（“/pipe/1“O_WRONLY|O_CREAT0666）;
		if?（fd1==-1）?{
			perror（“writer:?/pipe/1“）;
			_exit（1）;
		}
		release_sem（sem1）;
		/*?wait?for?other?side?to?open?the?pipe?1?*/
		acquire_sem（sem2）;
		/*?wait?for?creation?of?pipe?2?*/
		acquire_sem（sem1）;
		fd2=open（“/pipe/2“O_RDONLY）;
		if?（fd2==-1）?{
			perror（“/pipe/2“）;
			_exit（1）;
		}
		release_sem（sem2）;
		dup2（fd20）;
		dup2（fd11）;
		system（argv[2]）;

		_exit（1）;
	}
	acquire_sem（sem1）;
	fd1=open（“/pipe/1“O_RDONLY）;
	release_sem（sem2）;
	if?（fd1==-1）?{
		perror（“/pipe/1“）;
		exit（1）;
	}
	fd2=open（“/pipe/2“O_WRONLY|O_CREAT0666）;
	if?（fd2==-1）?{
		perror（“writer:?/pipe/2“）;
		exit（1）;
	}
	release_sem（sem1）;
	/*?wait?for?child?to?open?...?*/
	acquire_sem（sem2）;
	dup2（fd10）;
	dup2（fd21）;
	system（argv[1]）;
	exit（0）;
}