SplFileObject::ftruncate

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

SplFileObject::ftruncate — Truncates the file to a given length

说明

public SplFileObject::ftruncate(int $size): bool

Truncates the file to size bytes.

参数

size

The size to truncate to.

注意:

If size is larger than the file it is extended with null bytes.

If size is smaller than the file, the extra data will be lost.

返回值

成功时返回 true， 或者在失败时返回 false。

示例

示例 #1 SplFileObject::ftruncate() example

<?php
// Create file containing "Hello World!"
$file = new SplFileObject("/tmp/ftruncate", "w+");
$file->fwrite("Hello World!");

// Truncate to 5 bytes
$file->ftruncate(5);

// Rewind and read data
$file->rewind();
echo $file->fgets();
?>

以上示例的输出类似于：

Hello

参见