#35090 [Asn->Bgs]: file i/o is not buffered

ID: 35090 Updated by: iliaa@php.net Reported By: askalski at gmail dot com -Status: Assigned +Status: Bogus Bug Type: Filesystem function related Operating System: linux PHP Version: 5CVS-2005-11-03 (snap) Assigned To: wez New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php PHP does not do any buffering itself, instead it uses the system's file io buffering function to set the buffer. There is already a feature request open to enable in-php buffering. Previous Comments: ------------------------------------------------------------------------ [2005-11-03 21:29:08] derick@php.net Can you please answer why this is not a bug Wez? I forgot the reason :) ------------------------------------------------------------------------ [2005-11-03 19:16:09] askalski at gmail dot com Description: ------------ The documentation for stream_set_write_buffer() says that fwrite()s are buffered at 8K by default. In reality, it does not buffer at all. Any attempt to call stream_set_write_buffer() on a regular file handle results in failure. Reproduce code: --------------- $fh = fopen("asdf", "w"); // write some data using the default buffering for ($i = 0; $i < 5; $i++) fwrite($fh, "test"); // demonstrate that stream_set_write_buffer fails $n = stream_set_write_buffer($fh, 8192); if ($n != 0) echo "stream_set_write_buffer failed\n"; // write some more data to demonstrate the failure for ($i = 0; $i < 5; $i++) fwrite($fh, "again"); fclose($fh); Expected result: ---------------- PHP should buffer its I/O, and strace should log a single write(). stream_set_write_buffer() should not fail on regular files. Actual result: -------------- Output: stream_set_write_buffer failed Abridged strace output: open("/tmp/php5-200511031730/asdf", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3 fstat64(3, {st_mode=S_IFREG|0600, st_size=0, ...}) = 0 lseek(3, 0, SEEK_CUR) = 0 write(3, "test", 4) = 4 write(3, "test", 4) = 4 write(3, "test", 4) = 4 write(3, "test", 4) = 4 write(3, "test", 4) = 4 write(1, "stream_set_write_buffer failed\n", 31) = 31 write(3, "again", 5) = 5 write(3, "again", 5) = 5 write(3, "again", 5) = 5 write(3, "again", 5) = 5 write(3, "again", 5) = 5 close(3) = 0 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=35090&edit=1