SplFileObject::ftruncate

(PHP 5 >= 5.1.0, PHP 7)

SplFileObject::ftruncateTruncates the file to a given length

설명

public bool SplFileObject::ftruncate ( int $size )

Truncates the file to size bytes.

인수

size

The size to truncate to.

Note:

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.

반환값

성공 시 TRUE를, 실패 시 FALSE를 반환합니다.

예제

Example #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();
?>

위 예제의 출력 예시:

Hello

참고

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User Contributed Notes 1 note

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irvinezega at hotmail dot com
1 year ago
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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