bglenden@colobus.cv.nrao.edu (Brian Glendenning) (04/30/91)
I need to get command line arguments into a Fortran program that has
some C linked in, but no C main().
On other systems I have either
1) Used a Fortran library call or
2) Accessed an extern char** symbol from a C routine
Since the 720 short-term loaner has almost no documentation associated
with it, I don't know how to do either. Could some one let me know?
Thanks.
Brian
--
Brian Glendenning - National Radio Astronomy Observatory
bglenden@nrao.edu bglenden@nrao.bitnet (804) 296-0286john@hpucph.hp.com (John Damm Srensen) (05/06/91)
Unfortunately there is no suported interface to initialize the
Fortran environment from a C program.
But still there is away which on a 700/800 is like this:
main(argc,argv,envp)
int argc;
char **argv,**envp;
{
FTN_SET_AR(argc,argv,envp);
FTN_F_INIT();
printf("Arg 1 : %s\n",argv[1]);
/* From here on you may call Fortran routines which
use Fortran I/O or Fortran intrinsics like getarg igetarg
*/
}
john@hpucph.hp.com Speaking for myself only.jbc@hpcupt3.cup.hp.com (Jeff Caldwell) (05/07/91)
>I need to get command line arguments into a Fortran program that has >some C linked in, but no C main(). > >On other systems I have either >1) Used a Fortran library call or >2) Accessed an extern char** symbol from a C routine > >Since the 720 short-term loaner has almost no documentation associated >with it, I don't know how to do either. Could some one let me know? >Thanks. > >Brian Brian, To my knowledge, on the HP 700 series machine, their are a number of ways to get ahold of the command line arguments from Fortran. Below, I will describe two ways that I am familiar with: the PROGRAM statement and use of intrinsics (igetarg and iargc). The PROGRAM statement can be used to access information from the command line as follows: PROGRAM parm(arg1, arg2, arg3) CHARACTER*15 arg1, arg2, arg3 INTEGER atoi ! system conversion routine arg1(15:15) = char(0) ! Put nulls at the end of the strings for "atoi". arg2(15:15) = char(0) arg3(15:15) = char(0) iarg1 = atoi(arg1) ! ATOI can be used if the arguments are numeric. iarg2 = atoi(arg2) ! ATOI will convert ascii strings to integers. iarg3 = atoi(arg3) PRINT *, "INITIAL VALUES:", arg1, arg2, arg3 PRINT *, "NUMERIC EQUIVALENT:", iarg1, iarg2, iarg3 END % f77 program.f % a.out 10 20 30 INITIAL VALUES:10 20 30 NUMERIC EQUIVALENT: 10 20 30 % a.out testing command args INITIAL VALUES:testing command args NUMERIC EQUIVALENT: 0 0 0 % a.out mixed 30.3 args INITIAL VALUES:mixed 30.3 args NUMERIC EQUIVALENT: 0 30 0 Simply using the program statement is fairly easy. However, a more general way to access command-line arguments from series 700 Fortran is to use the igetarg() and iargc() functions. The igetarg() function requires 3 arguments: igetarg(n, str, slen) where: n is an integer specifying which command-line argument is requested. str is a character variable that will contain the requested command- line argument, padded with blanks on the end. slen is an integer specifying the maximum length of str, so that the routine knows how far to pad the string with blanks. note: the number of significant characters in "str" is returned as the value of the function igetarg. -1 is returned if the argument doesn't exist. note: The name of the program being run is the zeroth argument. iargc() return the number of parameters actually present on the command- line. Example: program args character*30 s integer numargs, length numargs = iargc() do 10, i = 0, numargs length = igetarg(i, s, 30) print *, "ARG ", i, " : ", s 10 continue end % f77 program.f % a.out testing 1 2 3 of the program ARG 0 : a.out ARG 1 : testing ARG 2 : 1 ARG 3 : 2 ARG 4 : 3 ARG 5 : of ARG 6 : the ARG 7 : program Good Luck, Jeff Caldwell Disclaimer: All information presented here is not an official statement of H.P. It is provided only for informative purposes and does not constitute a guarantee from HP. Only my opinion is presented here, not HP's ...
kgo@hpuerca.HP.COM (Kelly Oden) (05/07/91)
bglenden@colobus.cv.nrao.edu (Brian Glendenning) writes: >I need to get command line arguments into a Fortran program that has >some C linked in, but no C main(). > >Since the 720 short-term loaner has almost no documentation associated >with it, I don't know how to do either. Could some one let me know? Try the following fortran intrinsics calls: Function iargc() is integer type and returns the number of parameters on the command line. igetarg(n, str, slen) ---called as function or subroutine where: n - integer specifying which command line arg to get str - character variable that will contain the arg requested slen - integer specifying max length of str(for padding). igetarg() returns the number of significant characters in str, otherwise -1. (when n=0, igetarg returns the program name) This is a little sketchy but I hope it helps.
bglenden@colobus.cv.nrao.edu (Brian Glendenning) (05/08/91)
In article <1340019@hpuerca.HP.COM> kgo@hpuerca.HP.COM (Kelly Oden) writes: bglenden@colobus.cv.nrao.edu (Brian Glendenning) writes: >I need to get command line arguments into a Fortran program that has >some C linked in, but no C main(). > >Since the 720 short-term loaner has almost no documentation associated >with it, I don't know how to do either. Could some one let me know? Try the following fortran intrinsics calls: Function iargc() is integer type and returns the number of parameters on the command line. igetarg(n, str, slen) ---called as function or subroutine This indeed worked, once I realized that iargc() needed to be called before igetarg (some setup, presumably). Brian -- Brian Glendenning - National Radio Astronomy Observatory bglenden@nrao.edu bglenden@nrao.bitnet (804) 296-0286
rd@hpdtczb.HP.COM (Dick Dowell) (05/08/91)
The "iargc" and "igetarg" solutions posted are good ones. I have found
that some machines (notably the series 800, but that was a few years
ago) don't recognize igetarg. By using the "guess method" I came upon
a call to "getarg" which is
call getarg(num,arg)
where "num" is the argument number, arg is character variable to get argument.
This works on Sun, and Apollo. On the 800, I believe argument 1 is the
program name, on the others it is the first argument. I use iargc on all
the machines to get the number of arguments (again, test this stuff before
using it).
Dick "compatibility?" Dowell (rd@dtc.hp.com)