|TRUNCATE(2)||System Calls Manual||TRUNCATE(2)|
ftruncate — truncate or
extend a file to a specified length
char *path, off_t
causes the file named by path or referenced by
fd to be truncated or extended to
length bytes in size. If the file was larger than this
size, the extra data is lost. If the file was smaller than this size, it
will be extended as if by writing bytes with the value zero. With
the file must be open for writing.
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
ftruncate() will fail if:
truncate() may return the
NAME_MAXcharacters, or an entire pathname (including the terminating NUL) exceeded
ftruncate() may return the following
ftruncate() functions conform to
IEEE Std 1003.1-2008 (“POSIX.1”).
ftruncate() system calls first appeared in
These calls should be generalized to allow ranges of bytes in a file to be discarded.
truncate() to extend a file is not
|February 11, 2020||OpenBSD-6.8|