commit d2e8e5132b806951a389ee87bccc7e55ccf4a02e Author: Siddhesh Poyarekar Date: Sun Nov 25 15:30:07 2012 +0530 Make fwrite return 0 on EOF diff --git a/libio/Makefile b/libio/Makefile index 9ccd6a0..83d90d0 100644 --- a/libio/Makefile +++ b/libio/Makefile @@ -59,7 +59,8 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \ tst-memstream1 tst-memstream2 \ tst-wmemstream1 tst-wmemstream2 \ bug-memstream1 bug-wmemstream1 \ - tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos bug-fclose1 tst-fseek + tst-setvbuf1 tst-popen1 tst-fgetwc bug-wsetpos bug-fclose1 tst-fseek \ + tst-fwrite-error ifeq (yes,$(build-shared)) # Add test-fopenloc only if shared library is enabled since it depends on # shared localedata objects. diff --git a/libio/iofwrite.c b/libio/iofwrite.c index d4610f7..e93a656 100644 --- a/libio/iofwrite.c +++ b/libio/iofwrite.c @@ -43,11 +43,19 @@ _IO_fwrite (buf, size, count, fp) written = _IO_sputn (fp, (const char *) buf, request); _IO_release_lock (fp); /* We have written all of the input in case the return value indicates - this or EOF is returned. The latter is a special case where we - simply did not manage to flush the buffer. But the data is in the - buffer and therefore written as far as fwrite is concerned. */ - if (written == request || written == EOF) + this. */ + if (written == request) return count; + /* It is possible that the data was written out into buffer and we just + failed to flush it out. However, this is not necessarily always the + case and we cannot really differentiate this with a case when a flush + failed and all of the data was not in the buffer. Hence, just return 0 + (the flush failure should already have set the errno) and let the user + decide what to do. A future enhancement could be to find out how much + data is in the buffer and return that as a short write instead of just + 0. */ + else if (written == EOF) + return 0; else return written / size; } diff --git a/libio/iofwrite_u.c b/libio/iofwrite_u.c index a1077ee..bc533dd 100644 --- a/libio/iofwrite_u.c +++ b/libio/iofwrite_u.c @@ -45,11 +45,19 @@ fwrite_unlocked (buf, size, count, fp) { written = _IO_sputn (fp, (const char *) buf, request); /* We have written all of the input in case the return value indicates - this or EOF is returned. The latter is a special case where we - simply did not manage to flush the buffer. But the data is in the - buffer and therefore written as far as fwrite is concerned. */ - if (written == request || written == EOF) + this. */ + if (written == request) return count; + /* It is possible that the data was written out into buffer and we just + failed to flush it out. However, this is not necessarily always the + case and we cannot really differentiate this with a case when a flush + failed and all of the data was not in the buffer. Hence, just return 0 + (the flush failure should already have set the errno) and let the user + decide what to do. A future enhancement could be to find out how much + data is in the buffer and return that as a short write instead of just + 0. */ + else if (written == EOF) + return 0; } return written / size; diff --git a/libio/tst-fwrite-error.c b/libio/tst-fwrite-error.c new file mode 100644 index 0000000..3c0cf49 --- /dev/null +++ b/libio/tst-fwrite-error.c @@ -0,0 +1,66 @@ +/* Test of fwrite() function, adapted from gnulib-tests in grep. + Copyright (C) 2011-2012 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, 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 +#include + +static int +do_test (void) +{ + char tmpl[] = "/tmp/tst-fwrite-error.XXXXXX"; + int fd = mkstemp (tmpl); + if (fd == -1) + { + printf ("mkstemp failed with errno %d\n", errno); + return 1; + } + FILE *fp = fdopen (fd, "w"); + if (fp == NULL) + { + printf ("fdopen failed with errno %d\n", errno); + return 1; + } + + char buf[5] = "world"; + setvbuf (fp, NULL, _IONBF, 0); + close (fd); + unlink (tmpl); + errno = 0; + + int ret = fwrite (buf, 1, sizeof (buf), fp); + if (ret != 0) + { + printf ("fwrite returned %d\n", ret); + return 1; + } + if (errno != EBADF) + { + printf ("Errno is not EBADF: %d\n", errno); + return 1; + } + if (ferror (fp) == 0) + { + printf ("ferror not set\n"); + return 1; + } + + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c"