topic Re: subroutine argument count in Software Archive

subroutine argument count

james1 — Sat, 12 Jan 2002 10:10:20 GMT

I'd like a way of returning the argument count to the current procedure. On OVMS IARGCOUNT() does this nicely, however other architectures do not support an argument count in the call frame. Therefore I was wondering if there is some intrinsic property that would return the quantity of formal arguments. This could of course be hard coded, but as the compiler has full knowledge of this value it would be more foolproof.

James

Re: subroutine argument count

Steven_L_Intel1 — Sun, 13 Jan 2002 01:36:48 GMT

There isn't an intrinsic to return the number of arguments, which is either fixed or unknown, depending on the call mechanism.

Steve

Re: subroutine argument count

james1 — Sun, 13 Jan 2002 11:51:12 GMT

Didn't think so...any possibility of implementing IARGCOUNT() for CVF, having it return the number of formal arguments rather than actual arguments so that the intrinsic would be available on both platforms? While the meaning would be a little different, one could argue that the only legitamite argument count under Windows is the format parameter count anyway?

James

Re: subroutine argument count

Steven_L_Intel1 — Mon, 14 Jan 2002 04:43:47 GMT

Note that only for STDCALL interfaces can the compiler know the argument count - for the C interface, there is no information at all. I'm having a hard time understanding how this would be useful to you, given that the caller always has to pass the same number of arguments.

Steve

Re: subroutine argument count

james1 — Sat, 19 Jan 2002 09:17:39 GMT

Sorry for the delay. This is because as a matter of course the iargmask routine is used in a large number of routines on the OVMS system, this works great, one just needs to know the maximum bit number to check. With OVMS you can check IARGCOUNT to figure that out and there is no code maintenance hassle when one adds a parameter. By porting this to Win IARGMASK still works and whether or not an interface is available to the caller optional arguments may be determined. All that is required is a placeholder actual parameter for each specified formal parameter and all is well. All that is missing is a argument count, or next best thing, maximum argument count since Win cannot handle variable argument lists in the first place. The alternative is simply to hard code the formal parameter count in each routine, but this is not as elegant and possibly prone to more errors. I hope that makes sense!

James

Re: subroutine argument count

Steven_L_Intel1 — Sat, 19 Jan 2002 09:21:22 GMT

Interesting, but this is really specific to your application - iargmask is not something we supply on VMS either.

Steve

Re: subroutine argument count

james1 — Sat, 19 Jan 2002 09:24:59 GMT

Re: subroutine argument count

james1 — Sat, 19 Jan 2002 09:28:39 GMT

Whoops, please substitute IARGPTR for IARGMASK in the above.

James