stream_set_read_buffer

(PHP 5 >= 5.3.3, PHP 7, PHP 8)

stream_set_read_buffer — Set read file buffering on the given stream

function stream_set_read_buffer(resource $stream, int $size): int

Sets the read buffer. It's the equivalent of stream_set_write_buffer(), but for read operations.

stream: The file pointer.
size: The number of bytes to buffer. If size is 0 then read operations are unbuffered. This ensures that all reads with fread() are completed before other processes are allowed to read from that input stream.

Returns 0 on success, or another value if the request cannot be honored.