|TRUNCATE(2)||System Calls Manual||TRUNCATE(2)|
ftruncate — truncate or
extend a file to a specified length
char *path, off_t
truncate() 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
ftruncate(), the file must be open
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 succeed unless:
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 28, 2016||OpenBSD-current|