gzseek

(PHP 4, PHP 5, PHP 7)

gzseek — Seek on a gz-file pointer

说明

gzseek ( resource $zp , int $offset [, int $whence = SEEK_SET ] ) : int

Sets the file position indicator for the given file pointer to the given offset byte into the file stream. Equivalent to calling (in C) gzseek(zp, offset, SEEK_SET).

If the file is opened for reading, this function is emulated but can be extremely slow. If the file is opened for writing, only forward seeks are supported; gzseek() then compresses a sequence of zeroes up to the new starting position.

参数

zp

The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().

offset

The seeked offset.

whence

whence values are:

SEEK_SET - Set position equal to offset bytes.
SEEK_CUR - Set position to current location plus offset.

If whence is not specified, it is assumed to be SEEK_SET.

返回值

Upon success, returns 0; otherwise, returns -1. Note that seeking past EOF is not considered an error.

范例

Example #1 gzseek() example

 <?php
$gz = gzopen('somefile.gz', 'r');
gzseek($gz,2);
echo gzgetc($gz);
gzclose($gz);
?>

参见

gztell() - Tell gz-file pointer read/write position
gzrewind() - Rewind the position of a gz-file pointer

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