Compiler Specific Operators

[tainter at ihlpg.UUCP]

> >In article <mit-eddi.2526> barmar at mit-eddie.UUCP (Barry Margolin) writes:
> >>...why not write the operations as function calls, and teach compilers
> >>to open-code calls to certain functions.
> 
> In article <503 at cubsvax.UUCP> peters at cubsvax.UUCP (Peter S. Shenkin) replies:
> >Yes;  I tried to send off a similar comment on the original posting, but
> >it never made it off site.  What I'd like to know is whether the draft
> >standard permits this, and what the net guru's think about it.
> >
> >In Chris Torek's comment on the original posting, he proposes a workaround
> >permitted by the draft ANSI, and notes that it is bug-prone.  If this means
> >that the draft standard doesn't permit "function calls" to be implemented 
> >otherwise, I'm curious what the objections are to this practice.
> 
> Actually, the workaround comes off as being recommended by the
> draft standard, at least to me.  I am not certain it is bug-prone,
> but it sure does `feel' odd.
> 
> Apparently the committee (or a large faction thereof) is quite
> concerned about ensuring that there is some easy way to ensure a
> `real function call'.  They want a standardised way of defeating
> in-line expansion, and have, at least for the nonce, settled upon
> `#undef funcname'.  A `#pragma' seems to me to be at least as good
> an idea; compilers that never open-code a function call can ignore
> this, while those that might perform this optimisation could be
> required to pay attention to at least this one pragma.  Then instead
> of
> 
> 	#include <math.h>
> 	#undef sin			/* make sure we get a function */
> 	...
> 
> we might have
> 
> 	#include <math.h>
> 	#pragma disable_inline(sin)	/* get a function */
> 	...
> 	#pragma enable_inline(sin)	/* back to possible inline */
> 	...
> 	#pragma disable_inline(sin)	/* back to function */
> 
> This has the advantage of being reversible, as well.
> -- 
> In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1516)
> UUCP:	seismo!umcp-cs!chris
> CSNet:	chris at umcp-cs		ARPA:	chris at mimsy.umd.edu

Has anyoe proposed :
#suspend	alpha
#restore	alpha
to allow temporary suspension of a macro.
#undef
would mean multiple defines to restore the macro, which could be a pain
to maintain, or imposes some odd coding conventions

--j.a.tainter