streamWrapper::stream_seek()

(PHP 4 >= 4.3.2, PHP 5, PHP 7)

Seeks to specific location in a stream

说明

This method is called in response tofseek().

The read/write position of the stream should be updated according to the$offsetand$whence.

参数

The stream offset to seek to.

Possible values:

• SEEK_SET- Set position equal to$offsetbytes.
• SEEK_CUR- Set position to current location plus$offset.
• SEEK_END- Set position to end-of-file plus$offset.

返回值

ReturnTRUEif the position was updated,FALSEotherwise.

注释

If not implemented,FALSEis assumed as the return value.Note:

Upon success,streamWrapper::stream_tell()is called directly after callingstreamWrapper::stream_seek().IfstreamWrapper::stream_tell()fails, the return value to the caller function will be set toFALSENote:

Not all seeks operations on the stream will result in this function being called. PHP streams have read buffering enabled by default (see alsostream_set_read_buffer()) and seeking may be done by merely moving the buffer pointer.

参见

• fseek()在文件指针中定位

Please notice that the return value of this function is a boolean but the return value of fseek is 0 for ok and -1 for failure.
Please use this implementation when working with files:
function stream_seek($offset, $whence) {
    if(0 === fseek($this->_handler, $offset, $whence)){
      return true;
    }
    return false;
}