php man page for dio_truncate

DIO_TRUNCATE(3) 							 1							   DIO_TRUNCATE(3)

dio_truncate - Truncates file descriptor fd to offset bytes

SYNOPSIS
       bool dio_truncate (resource  $fd, int  $offset)

DESCRIPTION
       dio_truncate(3) truncates a file to at most $offset bytes in size.

	If  the  file  previously was larger than this size, the extra data is lost. If the file previously was shorter, it is unspecified whether
       the file is left unchanged or is extended. In the latter case the extended part reads as zero bytes.

PARAMETERS
	      o $fd
		- The file descriptor returned by dio_open(3).

	      o $offset
		- The offset in bytes.

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

NOTES
       Note

	      This function is not implemented on Windows platforms.

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