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v0.8.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision a8424940b4873791fc178a9f19a7bf1779a6cf42 authored by Miss Islington (bot) on 24 August 2019, 18:33:18 UTC, committed by Raymond Hettinger on 24 August 2019, 18:33:18 UTC 
bpo-14112: Allow beginners to explore shallowness in greater depth ;-) (GH-15465) (GH-15469)
 
(cherry picked from commit 69ee87e99cfe0b79389cffa92d126af868baf353)

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
1 parent d5a66bc
Raw File
Tip revision: a8424940b4873791fc178a9f19a7bf1779a6cf42 authored by Miss Islington (bot) on 24 August 2019, 18:33:18 UTC
bpo-14112: Allow beginners to explore shallowness in greater depth ;-) (GH-15465) (GH-15469)
Tip revision: a842494
dup2.c 
/*
 * Public domain dup2() lookalike
 * by Curtis Jackson @ AT&T Technologies, Burlington, NC
 * electronic address:  burl!rcj
 *
 * dup2 performs the following functions:
 *
 * Check to make sure that fd1 is a valid open file descriptor.
 * Check to see if fd2 is already open; if so, close it.
 * Duplicate fd1 onto fd2; checking to make sure fd2 is a valid fd.
 * Return fd2 if all went well; return BADEXIT otherwise.
 */

#include <fcntl.h>
#include <unistd.h>

#define BADEXIT -1

int
dup2(int fd1, int fd2)
{
    if (fd1 != fd2) {
        if (fcntl(fd1, F_GETFL) < 0)
            return BADEXIT;
        if (fcntl(fd2, F_GETFL) >= 0)
            close(fd2);
        if (fcntl(fd1, F_DUPFD, fd2) < 0)
            return BADEXIT;
    }
    return fd2;
}
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