Re: File/Record locking in Ada

[kst@sd.aonix.com (Keith Thompson)]

In <01bc259a$a035e850$fc00af88@godiva> "Keith Allan Shillington" <keith@sd.aonix.com> writes:
> Hmmm.  That would be a protected type.

I don't think so.  A protected type can protect access to a resource
within a single (possibly multi-tasking) program, but not between
different programs running independently on the same system.  Since files
are shared across multiple independent programs, protected types won't
work for file locking.

What you really want is something like the POSIX_File_Locking package.
If you don't have a working implementation of that, you may be able
to interface to fcntl().  According to IEEE 1003.5, the Get_Lock,
Set_Lock, and Wait_To_Set_Lock routines correspond to fcntl(F_GETLK),
fcntl(F_SETLK), and fcntl(F_SETLKW), respectively.

-- 
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