php man page for stream_set_blocking

STREAM_SET_BLOCKING(3)							 1						    STREAM_SET_BLOCKING(3)

stream_set_blocking - Set blocking/non-blocking mode on a stream

SYNOPSIS
       bool stream_set_blocking (resource  $stream, int  $mode)

DESCRIPTION
	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).

PARAMETERS
	      o $stream
		- The stream.

	      o $mode
		-  If  $mode  is  0,  the given stream will be switched to non-blocking mode, and if 1, it will be switched to blocking mode. This
		affects calls like fgets(3) and fread(3) that read from the stream. In non-blocking mode an fgets(3) call will always return right
		away while in blocking mode it will wait for data to become available on the stream.

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

NOTES
       Note

	       This function was previously called as set_socket_blocking(3) and later socket_set_blocking(3) but this usage is deprecated.

SEE ALSO 
stream_select(3).
PHP Documentation Group 												    STREAM_SET_BLOCKING(3)