1 /* $OpenBSD: pread.c,v 1.2 2003/07/31 21:48:09 deraadt Exp $ */ 2 /* 3 * Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain. 4 */ 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <unistd.h> 8 #include <err.h> 9 #include <fcntl.h> 10 11 int 12 main(int argc, char *argv[]) 13 { 14 char temp[] = "/tmp/dup2XXXXXXXXX"; 15 const char magic[10] = "0123456789"; 16 char c; 17 int fd; 18 19 if ((fd = mkstemp(temp)) < 0) 20 err(1, "mkstemp"); 21 remove(temp); 22 23 if (write(fd, magic, sizeof(magic)) != sizeof(magic)) 24 err(1, "write"); 25 26 if (lseek(fd, 0, SEEK_SET) != 0) 27 err(1, "lseek"); 28 29 if (read(fd, &c, 1) != 1) 30 err(1, "read1"); 31 32 if (c != magic[0]) 33 errx(1, "read1 %c != %c", c, magic[0]); 34 35 if (pread(fd, &c, 1, 7) != 1) 36 err(1, "pread"); 37 38 if (c != magic[7]) 39 errx(1, "pread %c != %c", c, magic[7]); 40 41 if (read(fd, &c, 1) != 1) 42 err(1, "read2"); 43 44 if (c != magic[1]) 45 errx(1, "read2 %c != %c", c, magic[1]); 46 47 return 0; 48 } 49