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CS 456 - Systems Programming
Spring 2024
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Displaying ./code/jan31/fd3.c
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
int main (int argc, char **argv){
if (argc < 4){
fprintf(stderr, "Usage %s file1 file2 file3\n",argv[0]);
exit(1);
}
//open a file, print it's file descriptor, then exit)
int fd1 = open(argv[1], O_RDONLY);
int fd2 = open(argv[2], O_RDONLY);
int fd3 = open(argv[3], O_RDONLY);
printf("fd of %s: %d\n", argv[1], fd1);
printf("fd of %s: %d\n", argv[2], fd2);
printf("fd of %s: %d\n", argv[3], fd3);
close(fd1);
close(fd2);
fd2 = open(argv[2], O_RDONLY);
printf("fd of %s again: %d\n", argv[2], fd2);
printf("fd of %s again: %d\n", argv[3], fd3);
close(fd2);
close(fd3);
return 0;
}
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