SplFileObject::ftruncate()

(PHP 5 >= 5.1.0, PHP 7)

Truncates the file to a given length

说明

Truncates the file to$sizebytes.

参数

The size to truncate to.

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

If$sizeis 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。

范例

SplFileObject::ftruncate() example

以上例程的输出类似于：

Hello

参见

• ftruncate()将文件截断到给定的长度

I suppose a fair number of us know this: 
However, for those who don't:- 
If you are truncating a file, say, to $fileObject->ftruncate(0), then, it may be advisable to call $fileObject->fseek(0) first (before you call '$fileObject->ftruncate'). 
On inspection, I was encountering 'NULL' characters at the beginning of a, or the, file. 
Hence, from what I have surmised; when 'ftruncate()' is called, the file pointer does NOT move to the beginning (or, at least, the required position) of the file.
This issue cost me a fair amount of time to figure out, so I hope it helps someone.

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