dup2_example - pipe(fd write to fd[1 read from fd[0 int rc...

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#include <stdio.h> #include <sys/types.h> #include <sys/uio.h> #include <unistd.h> #include <stdlib.h> #include <fcntl.h> /* * A wrapper function for dup2 so we don't duplicate this error * checking code */ void Dup2(int fd1, int fd2) { if (dup2(fd1, fd2) == -1) { perror("dup2"); exit(1); } } void Close(int fileno){ if (close(fileno) == -1) { perror("close"); exit(1); } } int main() { int filedes = open("file1", O_RDONLY); Dup2(filedes, fileno(stdin)); Close(filedes); int fd[2];
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Unformatted text preview: pipe(fd); // write to fd[1], read from fd[0] int rc = fork(); if (rc < 0) { perror("fork"); exit(1); } else if (rc == 0) { // I'm the child Close(fd[0]); // close the end of the pipe that I don't need Dup2(fd[1], fileno(stdout)); Close(fd[1]); execl("/usr/bin/sort", "sort", (char *) 0); } else { // I'm the parent Close(fd[1]); Dup2(fd[0], fileno(stdin)); Close(fd[0]); execl("/usr/bin/uniq","uniq", (char *) 0); } }...
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