ftruncate



ftruncate

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the truncate() and ftruncate() functions cause the regular file named by path or referenced by fd to be truncated to a size of precisely length bytes.

ftruncate

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the ftruncate() function causes the regular file referenced by fildes to have a size of length bytes. the truncate() function causes the regular file named by path to have a size of length bytes. if the file previously was larger than length, the extra data is discarded. if it was previously shorter than length, it is unspecified whether 

ftruncate

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if fildes is not a valid file descriptor open for writing, the ftruncate() function shall fail. if fildes refers to a regular file, the ftruncate() function shall cause the size of the file to be truncated to length. if the size of the file previously exceeded length, the extra data shall no longer be available to reads on the file. if the file previously 

ftruncate

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years ago. writing after ftruncate. i didnt expect that i can write in the middle of nowhere. i thought that i would write at the beginning of the file but the first bytes were filled automatically with nulls followed by "": <?php $str = ; $str = ; $datei = "test.txt"; $dh = fopen($datei,"w"); fwrite($dh, $str); fclose($dh);

ftruncate

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les appels truncate() et ftruncate() tronquent le fichier référencé par path ou par le descripteur fd à une longueur d'exactement length octets. si le fichier était plus long, les données supplémentaires sont perdues. si le fichier était plus court, il est étendu, et la portion supplémentaire est remplie d'octets nuls 

ftruncate

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the ftruncate() function truncates the file indicated by the open file descriptor fildes to the indicated length. fildes must be a regular file that is open for writing. if the file size exceeds length, any extra data is discarded. if the file size is smaller than length, bytes between the old and new lengths are read as zeros. a change to 

ftruncate

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the truncate and ftruncate functions cause the regular file named by path or referenced by fd to be truncated to a size of precisely length bytes. if the file previously was larger than this size, the extra data is lost. if the file previously was shorter, it is extended, and the extended part reads as zero bytes. the file pointer is not 

ftruncate

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specifically, ftruncate() sets the size of the file referenced by the descriptor fildes to length bytes. if the file was previously longer than length, bytes past length are lost. if the file was shorter, bytes between the old and the new length are read in as zeros. the effective user id of the process must have write permission for the 

ftruncate

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this can be done with the truncate and ftruncate functions. they were introduced in bsd unix. ftruncate was later added to posix.. some systems allow you to extend a file (creating holes) with these functions. this is useful when using memorymapped i/o (see memorymapped i/o), where files are not automatically 

ftruncate

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if the size of the file was previously shorter than length, the file size is extended with nul characters (similar to the f_allocsp option to fcntl()). the value of the seek pointer isn't modified by a call to ftruncate(). upon successful completion, the ftruncate() function marks the st_ctime and st_mtime fields of the file for update.