(PHP 4 >= 4.3.0, PHP 5, PHP 7)

stream_set_blockingSet blocking/non-blocking mode on a stream


bool stream_set_blocking ( resource $stream , bool $mode )

Sets blocking or non-blocking mode on a stream.

This function works for any stream that supports non-blocking mode (currently, regular files and socket streams).



The stream.


If mode is FALSE, the given stream will be switched to non-blocking mode, and if TRUE, it will be switched to blocking mode. This affects calls like fgets() and fread() that read from the stream. In non-blocking mode an fgets() call will always return right away while in blocking mode it will wait for data to become available on the stream.


성공 시 TRUE를, 실패 시 FALSE를 반환합니다.



This function was previously called as set_socket_blocking() and later socket_set_blocking() but this usage is deprecated.


  • stream_select() - Runs the equivalent of the select() system call on the given arrays of streams with a timeout specified by tv_sec and tv_usec
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User Contributed Notes 3 notes

10 years ago
On Windows this function does not work with pipes opened with proc_open (,,
MagicalTux at ookoo dot org
16 years ago
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.
ayon at hyurl dot com
6 years ago
It is necessary to be noted that stream_set_blocking() and stream_set_timeout() does not work width standard I/O streams, such as STDIN and STDOUT.
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