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/* $OpenBSD: pread.c,v 1.3 2011/11/05 15:43:04 guenther Exp $ */
/*
* Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
int
main(int argc, char *argv[])
{
char temp[] = "/tmp/dup2XXXXXXXXX";
const char magic[10] = "0123456789";
char c;
int fd, ret;
if ((fd = mkstemp(temp)) < 0)
err(1, "mkstemp");
remove(temp);
if (write(fd, magic, sizeof(magic)) != sizeof(magic))
err(1, "write");
if (lseek(fd, 0, SEEK_SET) != 0)
err(1, "lseek");
if (read(fd, &c, 1) != 1)
err(1, "read1");
if (c != magic[0])
errx(1, "read1 %c != %c", c, magic[0]);
if (pread(fd, &c, 1, 7) != 1)
err(1, "pread");
if (c != magic[7])
errx(1, "pread %c != %c", c, magic[7]);
if (read(fd, &c, 1) != 1)
err(1, "read2");
if (c != magic[1])
errx(1, "read2 %c != %c", c, magic[1]);
close(fd);
/* also, verify that pread fails on ttys */
fd = open("/dev/tty", O_RDWR);
if (fd < 0)
printf("skipping tty test\n");
else if ((ret = pread(fd, &c, 1, 7)) != -1)
errx(1, "pread succeeded on tty, returning %d", ret);
else if (errno != ESPIPE)
err(1, "pread");
return 0;
}
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