stream_select
stream_set_blocking does not unblock streams opened with popen. (tested in php 5.1.6)
stream_set_blocking
(PHP 4 >= 4.3.0, PHP 5)
stream_set_blocking — ストリームのブロックモードを有効にする / 解除する
説明
bool stream_set_blocking
( resource $stream
, int $mode
)
mode が 0 の時、ストリームは 非ブロックモードに切り替えられ、1 の場合は、 ブロックモードに切り替えられます。このモードの違いは、 fgets() や fread() といった、ストリームからデータを読む関数に影響します。 非ブロックモードにおいては fgets() を呼び出すと どんな場合でもただちに呼び出し元に戻りますが、フロッグモードの場合では、 ストリームがデータを読み出せる状態になるまで待ちつづけます。
成功した場合に TRUE を、失敗した場合に FALSE を返します。
以前、この関数は、 set_socket_blocking() または、後に socket_set_blocking() と呼ばれていましたが、 これらの関数は廃止されました。
注意: PHP 4.3 より前のバージョンでは、この関数は ソケットべースのストリームにしか機能しませんでした。 PHP 4.3 より、この関数は、非ブロックモードを サポートするすべてのストリームにおいて利用可能となりました。 (現在サポートするのは、通常のファイルストリームとソケットストリームのみです。)
stream_select() も参照ください。
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User Contributed Notesstream_set_blocking
arjuna
06-Aug-2008 01:31
06-Aug-2008 01:31
22-Mar-2007 10:33
A concise description of Blocking vs. Non-blocking:
http://tinyurl.com/ype2j7
http://www.franz.com/support/documentation/7.0/ doc/streams.htm#block-non-block-3
5.2.1 Blocking behavior in simple-streams
There are three modes of blocking behavior when writing
items in a sequence to a stream or filling a sequence with items read from a stream. The issue is what to do when (for writing) the entire sequence cannot be written and (for reading) the entire sequence cannot be filled, but no EOF is encountered. (By `the entire sequence', we mean that part specified by start and end if those are supplied.) Here are the modes and a description of what happens in that mode if the whole operation does not complete and no EOF is encountered.
1. Blocking mode: the system blocks (waits or hangs) until the operation can be completed.
2. Blocking/Non-Blocking (B/NB) mode: the system only blocks on the first element of the sequence: if it cannot be written or read, the system blocks. If the first element is successfully written or read, and a subsequent element cannot be written or read, the function doing the writing/reading returns, typically with the return value(s) indicating exactly what was accomplished.
3. Non-Blocking mode: the system never blocks. If an element cannot be written or read, the function doing the writing/reading returns, typically with the return value(s) indicating exactly what was accomplished.
galvao at galvao dot eti dot br
15-Dec-2006 06:58
15-Dec-2006 06:58
Please notice that this function will not work as for PHP 5.2.0 at least on Win32 systems. It probably won't work on Linux boxes either.
PHP just ignores the function and blocking remains active.
For more information take a look at Bug #36918.
MagicalTux at ookoo dot org
08-Sep-2006 09:13
08-Sep-2006 09:13
When you use fwrite() on a non-blocking stream, data isn't discarded silently as t dot starling said.
Remember that fwrite() returns an int, and this int represents the amount of data really written to the stream. So, if you see that fwrite() returns less than the amount of written data, it means you'll have to call fwrite() again in the future to write the remaining amount of data.
You can use stream_select() to wait for the stream to be available for writing, then continue writing data to the stream.
Non-blocking streams are useful as you can have more than one non-blocking stream, and wait for them to be available for writing.
t dot starling at physics dot unimelb dot edu dot au
08-Sep-2005 02:02
08-Sep-2005 02:02
Warning: if you write too much data to a stream in non-blocking mode and fill the buffer, the excess will be silently discarded. Observed in PHP 4.4.0 under linux.