Type: New Feature
Affects Version/s: None
Fix Version/s: None
from man truncate:
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 changed.
If the size changed, then the ctime and mtime fields for the file are updated, and suid and sgid mode bits may be cleared.
With ftruncate, the file must be open for writing; with truncate, the file must be writable.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.