Avifinfo

read() │ WP 1.0

Reads bytes and advances the stream position by the same count.

No Hooks.

Return

binary. string|false The raw bytes or false on failure.

Usage

read( $handle, $num_bytes );
$handle(stream) (required)
Bytes will be read from this resource.
$num_bytes(int) (required)
Number of bytes read. Must be greater than 0.

read() code WP 6.7.1

wp-includes/class-avif-info.php 
function read( $handle, $num_bytes ) {
  $data = fread( $handle, $num_bytes );
  return ( $data !== false && strlen( $data ) >= $num_bytes ) ? $data : false;
}