我遇到了问题。试图写一个简单的程序,其中分叉一次FIFO与/ dev/urandom
父进程从/ dev/urandom发送子字节,子进程将它们输出到屏幕(15行,每行十六进制)。问题是:当我第一次打开编译PROGRAMM输出的样子:
B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 ... B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0 B0
(并不总是 “B0”,但肯定同一个字节) 当我运行同一程序(不重新编译)再次输出似乎是好的...任何想法?
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <termios.h>
int main(int argc, char *argv[])
{
char bufforek[256];
printf("P1: READING /dev/urandom\n");
FILE *file_ptr = fopen("/dev/urandom", "r");
int file=open("FIFO",O_RDWR);
mkfifo("FIFO",0666);
char pomoc;
int hexa;
int i=1;
if(fork()==0)
{
char bufforek1[256];
while(read(file,bufforek1,sizeof(bufforek1)))
{
pomoc = *bufforek1;
// printf("%hhX ", pom);
hexa = (int)pomoc;
pomoc = *bufforek1;
printf("%hhX ", pomoc);
if(i==15)
{
printf("\n");
i=1;
}
else i++;
// write(pipe_table[1],bufforek,sizeof(bufforek));
}
return 0;
}
while ((fgets(bufforek, sizeof(bufforek), file_ptr))!=NULL) write(file, bufforek, sizeof(bufforek));
unlink("FIFO");
return 0;
}
几个问题......为什么在打开它后创建fifo'mkfifo()'?而且你没有检查从每个fds读取的字节数量...... – rodrigo