PD ftruncate needed

[Dave Decot]

> I probably would add it to an implemenation as a command to
> fcntl(), using similar syntax to the locking primitives, with
> similar power (being able to delete an arbitrary region, with or
> without modifiing the "seek" positions of parts of the stream,
> and allowing an implimentation to require "block aligned" deletes
> if the end of the file is not one of the boundaries).  Likely, no
> one would use this version either, but it wouldn't require
> another manual page...

System V.4 does exactly this; unfortunately, they use "struct flock"
for it, and the values of whence are still "SEEK_CUR", "SEEK_END", etc.
ICK.

Dave