woo@acf4.UUCP (04/29/87)
Is there anything comparable to getarg and iargc for subroutines or functions? How can a function determine the name of the function which calls it or the number of calling arguments, either in C or f77? Alex Woo woo@acf4.nyu.edu wooa@nyuacf.bitnet seismo!cmcl2!acf4!woo
joe@dayton.UUCP (Joseph P. Larson) (05/01/87)
In article <13160003@acf4.UUCP> woo@acf4.UUCP (Alex C. Woo) writes: > >Is there anything comparable to getarg and iargc for subroutines >or functions? How can a function determine the name of the function >which calls it or the number of calling arguments, either in C >or f77? This kind of thing is compiler- (and perhaps machine-) dependant. DEC FORTRAN won't tell you, for instance. I suspect most compilers won't give you the name of the function or subroutine for the simple reason that this means it would also have to keep this info in a table. If you then strip the program (an obvious UNIX term), your program is unlikely to work anymore. As for the number of arguments -- that's going to be dependent on your machine and compiler, as well. If you can't find the info, you might be able to write an assembly-language routine that will look at the info on the stack -- what you are looking for just might be there. -- UUCP: rutgers!dayton!joe Dayton Hudson Department Store Company ATT : (612) 375-3537 Joe Larson/MIS 1060 (standard disclaimer...) 700 on the Mall Mpls, Mn. 55408
normt@ihlpa.ATT.COM (N. R Tiedemann) (05/01/87)
In article <13160003@acf4.UUCP>, woo@acf4.UUCP (Alex C. Woo) writes: > Is there anything comparable to getarg and iargc for subroutines > or functions? How can a function determine the name of the function > which calls it or the number of calling arguments, either in C > or f77? > Alex Woo I'm not sure if this is standard or a specific implementation, but f77 on DEC machines uses a general purpose register (r5) as the argument pointer for both function and subroutine calls. The first thing on this list is the number of argument, then the address of each. The only real different between a function and subroutine in fortran is a function returns its value in r0. (again the r0 may be DEC specific.) I don't think there is any way to determine the calling function short of looking at the return address on the stack and comparing that to the loader map file, to see in which function that address lies. Not something to do in code. Hope this helps a little Norm Tiedemann ihnp4!ihlpa!normt AT&T Bell Labs Naperville, IL 60566
ken@rochester.ARPA (Ken Yap) (05/04/87)
If you want to do this just for the purposes of tracing calls and you
don't want to go around mucking with machine dependent stacks, you
could do it with a preprocessor that inserts two extra arguments in
front of every call.
call foobar(1, 3.0, 4.0)
becomes
call foobar('parent', 3, 1, 3.0, 4.0)
and the subroutine declaration has to be changed too, of course.
Of course, don't do this to library routines or intrinsics.
I don't have any idea how much work this is. Have fun.
Ken