+/* Test of POSIX compatible fflush() function.
+ Copyright (C) 2007 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 2, 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, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Written by Eric Blake, 2007. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdio.h>
+#include <unistd.h>
+
+int
+main (int argc, char *argv[])
+{
+ FILE *f;
+ char buffer[10];
+ int fd;
+
+ /* Create test file. */
+ f = fopen ("test-fflush.txt", "w");
+ if (!f || fwrite ("1234567890", 1, 10, f) != 10 || fclose (f) != 0)
+ {
+ fputs ("Failed to create sample file.\n", stderr);
+ unlink ("test-fflush.txt");
+ return 1;
+ }
+
+ /* Test fflush. */
+ f = fopen ("test-fflush.txt", "r");
+ fd = fileno (f);
+ if (!f || 0 > fd || fread (buffer, 1, 5, f) != 5)
+ {
+ fputs ("Failed initial read of sample file.\n", stderr);
+ fclose (f);
+ unlink ("test-fflush.txt");
+ return 1;
+ }
+ /* For deterministic results, ensure f read a bigger buffer. */
+ if (lseek (fd, 0, SEEK_CUR) == 5)
+ {
+ fputs ("Sample file was not buffered.\n", stderr);
+ fclose (f);
+ unlink ("test-fflush.txt");
+ return 1;
+ }
+ /* POSIX requires fflush-fseek to set file offset of fd. */
+ if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
+ {
+ fputs ("Failed to flush sample file.\n", stderr);
+ fclose (f);
+ unlink ("test-fflush.txt");
+ return 1;
+ }
+ /* Check that offset is correct. */
+ if (lseek (fd, 0, SEEK_CUR) != 5)
+ {
+ fputs ("File offset is wrong.\n", stderr);
+ fclose (f);
+ unlink ("test-fflush.txt");
+ return 1;
+ }
+ /* Check that file reading resumes at correct location. */
+ if (fgetc (f) != '6')
+ {
+ fputs ("Failed to read next byte of file.\n", stderr);
+ fclose (f);
+ unlink ("test-fflush.txt");
+ return 1;
+ }
+ fclose (f);
+ unlink ("test-fflush.txt");
+ return 0;
+}