Re: Problem when creating a.out and -convert big_endian compiler option

Hello,

Förster vom Silberwald wrote:

I must confess: I have never understood what this "implicit none" in
Fortran programs really means. I see it sometime when colleagues pass
over some Fortan programs to me.

Older (and it's still around) Fortran has the concept
of "implicit typing" where the first letter of a name
specifies the type. (Some programmers like to be able
to code without declarations, for example, like MATLAB code.)

Modern practice frowns on this practice. Starting with Fortran 90,
(well, actually starting with Mil Std 1753, but let's not split hairs),
Fortran has had a statement "implicit none" to disable the implicit
typing rules, and therefore force declaration of all variable names.

Thus, when reading older codes, sometimes the reader must check
the implicit statement to see the types of variable names.
If there's no implicit statement, default rules are in effect.
The default rules were: First letter in (A through H or O through Z),
the type is default real; First letter in (I through N), the type is
default integer.

If you have the time and you expect to be working on the code
for a while, it may be worthwhile to go through it and code
a declaration for each variable.

For one thing, you may well be lead to the bug you're facing now.

--

Dan Nagle
Purple Sage Computing Solutions, Inc.
.

Relevant Pages

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