| /* Test of fpurge() function. |
| Copyright (C) 2007-2020 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 <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Bruno Haible <bruno@clisp.org>, 2007. */ |
| |
| #include <config.h> |
| |
| /* None of the files accessed by this test are large, so disable the |
| fseek link warning if we are not using the gnulib fseek module. */ |
| #define _GL_NO_LARGE_FILES |
| #include <stdio.h> |
| |
| #include <string.h> |
| |
| #include "macros.h" |
| |
| #define TESTFILE "t-fpurge.tmp" |
| |
| int |
| main (void) |
| { |
| int check_filepos; |
| |
| for (check_filepos = 0; check_filepos <= 1; check_filepos++) |
| { |
| FILE *fp; |
| |
| /* Create a file with some contents. */ |
| fp = fopen (TESTFILE, "w"); |
| if (fp == NULL) |
| goto skip; |
| if (fwrite ("foobarsh", 1, 8, fp) < 8) |
| goto skip; |
| if (fclose (fp)) |
| goto skip; |
| |
| /* The file's contents is now "foobarsh". */ |
| |
| /* Open it in read-write mode. */ |
| fp = fopen (TESTFILE, "r+"); |
| if (fp == NULL) |
| goto skip; |
| if (fseek (fp, 3, SEEK_CUR)) |
| goto skip; |
| if (fwrite ("g", 1, 1, fp) < 1) |
| goto skip; |
| if (fflush (fp)) |
| goto skip; |
| if (fwrite ("bz", 1, 2, fp) < 2) |
| goto skip; |
| /* Discard pending write. */ |
| ASSERT (fpurge (fp) == 0); |
| /* Verify that when discarding pending output, the file position is set |
| back to where it was before the write calls. */ |
| if (check_filepos) |
| ASSERT (ftell (fp) == 4); |
| ASSERT (fclose (fp) == 0); |
| |
| /* Open it in read-only mode. */ |
| fp = fopen (TESTFILE, "r"); |
| if (fp == NULL) |
| goto skip; |
| /* Verify that the pending writes before the fpurge were really |
| discarded. */ |
| { |
| char buf[8]; |
| if (fread (buf, 1, 7, fp) < 7) |
| goto skip; |
| ASSERT (memcmp (buf, "foogars", 7) == 0); |
| } |
| /* Discard the buffered 'h'. */ |
| if (check_filepos) |
| ASSERT (ftell (fp) == 7); |
| ASSERT (fpurge (fp) == 0); |
| /* Verify that when discarding pending input, the file position is |
| advanced to match the end of the previously read input. */ |
| if (check_filepos) |
| ASSERT (ftell (fp) == 8); |
| ASSERT (getc (fp) == EOF); |
| ASSERT (fclose (fp) == 0); |
| |
| /* The file's contents is now "foogarsh". */ |
| |
| /* Ensure that purging a read does not corrupt subsequent writes. */ |
| fp = fopen (TESTFILE, "r+"); |
| if (fp == NULL) |
| goto skip; |
| if (fseek (fp, -1, SEEK_END)) |
| goto skip; |
| ASSERT (getc (fp) == 'h'); |
| ASSERT (getc (fp) == EOF); |
| if (check_filepos) |
| ASSERT (ftell (fp) == 8); |
| ASSERT (fpurge (fp) == 0); |
| if (check_filepos) |
| ASSERT (ftell (fp) == 8); |
| ASSERT (putc ('!', fp) == '!'); |
| if (check_filepos) |
| ASSERT (ftell (fp) == 9); |
| ASSERT (fclose (fp) == 0); |
| fp = fopen (TESTFILE, "r"); |
| if (fp == NULL) |
| goto skip; |
| { |
| char buf[10]; |
| ASSERT (fread (buf, 1, 10, fp) == 9); |
| ASSERT (memcmp (buf, "foogarsh!", 9) == 0); |
| } |
| ASSERT (fclose (fp) == 0); |
| |
| /* The file's contents is now "foogarsh!". */ |
| } |
| |
| remove (TESTFILE); |
| return 0; |
| |
| skip: |
| fprintf (stderr, "Skipping test: prerequisite file operations failed.\n"); |
| remove (TESTFILE); |
| return 77; |
| } |