Regarding Fortran Compiler Characteristics

[Tobias Burnus]

Dear all,

I have a remark regarding the Fortran Compiler Characteristics section,
http://www.gnu.org/software/autoconf/manual/html_node/Fortran-Compiler.html

There one can find for AC_FC_MAIN/AC_F77_MAIN:

"As discussed above, many Fortran libraries allow you to provide an entry
 point called (say) MAIN__ instead of the usual main, [...]"

That part is OK. However, it continues with

"Thus, when calling Fortran routines from C that perform things like I/O,
 one should use this macro and declare the "main" function like so:

          #ifdef __cplusplus
            extern "C"
          #endif
          int F77_MAIN(int argc, char *argv[]);
"

I believe this does not make much sense. For instance, a minimal
Fortran example ("END") compiled with gfortran (4.5, -fdump-tree-original)
looks as follows. (Note: This is not C but the dump of the internal
structure of the compiler, but it is close to C.)


MAIN__ () {
  (void) 0;
}

main (integer(kind=4) argc, character(kind=1) * * argv) {
  static integer(kind=4) options.0[8] = {68, 255, 0, 0, 0, 1, 0, 1};
  _gfortran_set_args (argc, argv);
  _gfortran_set_options (8, &options.0[0]);
  MAIN__ ();
  return 0;
}


[At least for GCC Fortran (gfortran) there is also no need to call
 _gfortran_set_args when doing I/O; it is only needed when accessing
 the command line. (_gfortran_set_options might be in rare cases
 useful when doing I/O, but only in very special cases; or for some
 other special needs such as turning on the run-time bounds checking.
 In any case that's out of scope for autoconf.)]

 * * *

As the list below shows, most compilers do the initialization via a
special function, which makes more sense. I think it could be useful to
provide by default an AC_* macro, but at least the manual should be
changed.


gfortran has:
  _gfortran_set_args (argc, argv);
g95 has:
  g95_runtime_start(argc, argv);
NAG f95 uses:
  f90_init(argc,argv);
Intel uses:
  for_rtl_init_ (&argc, argv);  /* Note the '&' */
g77 uses:
  f_setarg(argc,argv);

Tobias,
who is a gfortran mainatainer

PS: I read that the "goal is that 2.64 will be released no later
    than May 31st." Is this still the goal or when can 2.64 be
    expected?