Conference noted::hackers_v1

458.0. "Number of arguments passed to a routine?" by LA780::LONGO (Bob Longo) Thu Apr 30 1987 15:24

    [also entered in the VMS notes file]

    I have a customer who is converting FORTRAN code to run on his new
    VAXes.  The FORTRAN on his old machine allowed a subroutine to
    determine the number of arguments passed to it.
    
    I have written a small routine than can be called from FORTRAN
    subroutine to determine the number of arguments passed to the FORTRAN
    subroutine.  It does this by examining the previous call frame on
    the stack and returning the argument count.  The routine I wrote
    consists of the usual argument validation and:
    	SAVAP=8
    	MOVZBL	@SAVAP(FP),@4(AP)	;Return previous prev arg count
    
    My question is this:  Is FORTRAN guaranteed to follow the procedure
    calling standard (i.e. not pass arguments to the subroutine in
    registers)?  Can anyone think of a reason why this routine would
    break in the future?  It seems to work fine, but I may be overlooking
    something that would cause it to break later.
    
    Thanks,
    -Bob

    I have responded to this in vmsnotes  --  Barry