posix_app.c

来自「rtlinux3.0 的源代码」· C语言 代码 · 共 22 行

#include <fcntl.h>
#define NANOSECONDS_PER_TICK (double)((double)1000.00/(double)366.00) 
main(){
	int fd,count;
	struct { int count; unsigned int d;}D;
	double f;
	if( (fd = open("/dev/rtf0",O_RDONLY) ) < 0 ){
		perror("Can't open fifo");
		exit(0);
	}
	while( (read(fd,&D,sizeof(D))  == sizeof(D))){
		f = (double)D.d;
		f = ((f) * NANOSECONDS_PER_TICK)/1000;
		printf("Delay was %f microseconds\n",f);
		if(count && (count+1 != D.count))
			printf("Dropped a packet at %d ",count);
		count = D.count;
	}
}