//-------------------------------------------------------------------
//	run.cpp
//
//	This program was written in order to allow a user to see the
//	value of an application-program's exit-code: the application
//	will be executed as a child-process, and its exit-code shown
//	by the parent-prcess, which receives it by calling 'wait()'. 
//
//		compile using:  $ make run
//		execute using:  $ run <appname> {<arg1>, ... }
//
//	programmer: ALLAN CRUSE
//	written on: 03 MAY 2005
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <unistd.h>	// for fork(), execv()  
#include <stdlib.h>	// for exit() 
#include <sys/wait.h>	// for wait()

int main( int argc, char **argv )
{
	if ( argc == 1 ) { fprintf( stderr, "No argument\n" ); exit(1); }

	int	pid = fork();	// creates the child-process

	if ( pid == 0 ) // child-process executes application
		if ( execv( argv[1], argv+1 ) < 0 )
			{ perror( "execv" ); exit( 1 ); }

	// parent-process waits until child-process terminates
	int	status = 0;
	wait( &status );

	// parent retrieves and displays child's exit-status	
	if ( WIFEXITED( status ) ) 
		{
		printf( "process %s exited with ", argv[1] );
		printf( "status=%d \n", (char)WEXITSTATUS( status ) );
		}
}