/* Test of freading() function. Copyright (C) 2007-2021 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 . */ /* Written by Bruno Haible , 2007. */ #include /* 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 "freading.h" #include #include "macros.h" #define TESTFILE "t-freading.tmp" int main (void) { FILE *fp; /* Create a file with some contents. Write-only file is never reading. */ fp = fopen (TESTFILE, "w"); ASSERT (fp); ASSERT (!freading (fp)); ASSERT (fwrite ("foobarsh", 1, 8, fp) == 8); ASSERT (!freading (fp)); ASSERT (fclose (fp) == 0); /* Open it in read-only mode. Read-only file is always reading. */ fp = fopen (TESTFILE, "r"); ASSERT (fp); ASSERT (freading (fp)); ASSERT (fgetc (fp) == 'f'); ASSERT (freading (fp)); ASSERT (fseek (fp, 2, SEEK_CUR) == 0); ASSERT (freading (fp)); ASSERT (fgetc (fp) == 'b'); ASSERT (freading (fp)); fflush (fp); ASSERT (freading (fp)); ASSERT (fgetc (fp) == 'a'); ASSERT (freading (fp)); ASSERT (fseek (fp, 0, SEEK_END) == 0); ASSERT (freading (fp)); ASSERT (fclose (fp) == 0); /* Open it in read-write mode. POSIX requires a reposition (fseek, fsetpos, rewind) or EOF when transitioning from read to write; freading is only deterministic after input or output, but this test case should be portable even on open, after reposition, and at EOF. */ /* First a scenario with only fgetc, fseek, fputc. */ fp = fopen (TESTFILE, "r+"); ASSERT (fp); ASSERT (!freading (fp)); ASSERT (fgetc (fp) == 'f'); ASSERT (freading (fp)); ASSERT (fseek (fp, 2, SEEK_CUR) == 0); /* freading (fp) is undefined here, but fwriting (fp) is false. */ ASSERT (fgetc (fp) == 'b'); ASSERT (freading (fp)); /* This fseek call is necessary when switching from reading to writing. See the description of fopen(), ISO C 99 7.19.5.3.(6). */ ASSERT (fseek (fp, 0, SEEK_CUR) == 0); /* freading (fp) is undefined here, but fwriting (fp) is false. */ ASSERT (fputc ('x', fp) == 'x'); ASSERT (!freading (fp)); ASSERT (fseek (fp, 0, SEEK_END) == 0); /* freading (fp) is undefined here, because on some implementations (e.g. glibc) fseek causes a buffer to be read. fwriting (fp) is undefined as well. */ ASSERT (fclose (fp) == 0); /* Open it in read-write mode. POSIX requires a reposition (fseek, fsetpos, rewind) or EOF when transitioning from read to write; freading is only deterministic after input or output, but this test case should be portable even on open, after reposition, and at EOF. */ /* Here a scenario that includes fflush. */ fp = fopen (TESTFILE, "r+"); ASSERT (fp); ASSERT (!freading (fp)); ASSERT (fgetc (fp) == 'f'); ASSERT (freading (fp)); ASSERT (fseek (fp, 2, SEEK_CUR) == 0); /* freading (fp) is undefined here, but fwriting (fp) is false. */ ASSERT (fgetc (fp) == 'b'); ASSERT (freading (fp)); fflush (fp); /* freading (fp) is undefined here, but fwriting (fp) is false. */ ASSERT (fgetc (fp) == 'x'); ASSERT (freading (fp)); /* This fseek call is necessary when switching from reading to writing. See the description of fopen(), ISO C 99 7.19.5.3.(6). */ ASSERT (fseek (fp, 0, SEEK_CUR) == 0); /* freading (fp) is undefined here, but fwriting (fp) is false. */ ASSERT (fputc ('z', fp) == 'z'); ASSERT (!freading (fp)); ASSERT (fseek (fp, 0, SEEK_END) == 0); /* freading (fp) is undefined here, because on some implementations (e.g. glibc) fseek causes a buffer to be read. fwriting (fp) is undefined as well. */ ASSERT (fclose (fp) == 0); /* Open it in append mode. Write-only file is never reading. */ fp = fopen (TESTFILE, "a"); ASSERT (fp); ASSERT (!freading (fp)); ASSERT (fwrite ("bla", 1, 3, fp) == 3); ASSERT (!freading (fp)); ASSERT (fclose (fp) == 0); ASSERT (remove (TESTFILE) == 0); return 0; }