/* Test the read() function. Copyright (C) 2011-2015 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include #include #include "signature.h" SIGNATURE_CHECK (read, ssize_t, (int, void *, size_t)); #include #include #include #include "macros.h" int main (void) { const char *filename = "test-read.tmp"; int fd; /* Create a file with a simple contents. */ fd = open (filename, O_CREAT | O_WRONLY, 0600); ASSERT (fd >= 0); ASSERT (write (fd, "Hello World", 11) == 11); ASSERT (close (fd) == 0); /* Read from the middle of the file. */ fd = open (filename, O_RDONLY); ASSERT (fd >= 0); ASSERT (lseek (fd, 6, SEEK_SET) == 6); { char buf[10]; ssize_t ret = read (fd, buf, 10); ASSERT (ret == 5); ASSERT (memcmp (buf, "World", 5) == 0); } ASSERT (close (fd) == 0); /* Test behaviour for invalid file descriptors. */ { char byte; errno = 0; ASSERT (read (-1, &byte, 1) == -1); ASSERT (errno == EBADF); } { char byte; close (99); errno = 0; ASSERT (read (99, &byte, 1) == -1); ASSERT (errno == EBADF); } /* Clean up. */ unlink (filename); return 0; }