#pragma

[Rahul Dhesi]

In <9012050330.AA04857 at decpa.pa.dec.com> diamond at tkou02.enet.dec.com
("diamond at tkovoa") writes:

>In that case, why should unrecognized #pragmas be ignored?

A minor mistake.

Pragmas allow one to escape from the confines of the standard.  Such
escapes should always be done under the full control of the user.  A
good way to implement pragmas is to require that all pragmas that will
be recognized by a compiler be listed in a file, and any pragma not in
that file result in a warning.  This will minimize the probability 
that a switch in compilers, or a revision in the names of pragmas
interpreted by a compiler, won't cause surprises.

The current situation, such that some pragmas are silently obeyed,
while others are silently ignored, is a disaster waiting to happen.

    /* The "unroll-loop" pragma force loop unrolling, so our process
    will react well within the 0.5 milliseconds needed to avoid a
    nuclear explosion. */

    #pragma  unrolll_loop  /* Darn!  Got to get that keybounce fixed */
--
Rahul Dhesi <dhesi%cirrusl at oliveb.ATC.olivetti.com>
UUCP:  oliveb!cirrusl!dhesi