dcl2inc - postprocess ftnchek .dcl files to create separate INCLUDE
dcl2inc postprocessing declaration files output by ftnchek(1),
replacing unique COMMON block definitions by Fortran INCLUDE
statements. For each input .dcl file, a modified output .dcn file is
produced, together with include files named by the COMMON block name,
with filename extension .inc.
In addition, dcl2inc produces on stdout a list of Makefile dependencies
for the UNIX make(1) utility. These can be appended to the project
Makefile to ensure that any subsequent changes to .inc files provoke
recompilation of source files that include them.
dcl2inc warns about COMMONs which differ from their first occurrence,
and simply copies them to the output .dcn file, instead of replacing
them with an INCLUDE statement. Thus, any COMMON statements that are
found in the output .dcn files should be examined carefully to
determine why they differ: they may well be in error.
Replication of identical data, and bugs arising from subsequent
modification of only part of it, is a significant reason why Fortran
programming projects should require that COMMON declarations occur in
separate include files, so that there is only a single point of
definition of any global object.
Even though the Fortran INCLUDE statement was tragically omitted from
the 1977 Standard, it has long been implemented by virtually all
compiler vendors, and is part of the 1990 Standard. In practice, there
is therefore no portability problem associated with use of INCLUDE
statements, provided that one avoids nonportable file names. As long
as the code obeys Fortran’s limit of six-character alphanumeric names,
the filenames generated by dcl2inc will be acceptable on all current
popular operating systems.
Fortran’s default, or IMPLICIT, variable typing is deprecated in modern
programming languages, because it encourages sloppy documentation, and
worse, bugs due to misspelled variables, or variables that have been
truncated because they extend past column 72. If all variables used
are explicitly typed, and a compiler option is used to reject all
program units with untyped variables, variable spelling and truncation
errors can be eliminated.
Variable declarations that have been produced automatically by a tool
like ftnchek(1) or pfort(1) have a consistent format that facilitates
application of stream editors (e.g. to change array dimensions or
rename variables), and simple floating-point precision conversion tools
like d2s(1), dtoq(1), dtos(1), qtod(1), s2d(1), and stod(1).
The current version (2.9) of ftnchek(1) does not produce Fortran
EQUIVALENCE statements in .dcl files, so you must be careful to
preserve them when replacing original declarations with new ones from
.dcl or .dcn files.
d2s(1), dtoq(1), dtos(1), ftnchek(1), make(1), pfort(1), qtod(1),
Nelson H. F. Beebe, Ph.D.
Center for Scientific Computing
Department of Mathematics
University of Utah
Salt Lake City, UT 84112
Tel: +1 801 581 5254
FAX: +1 801 581 4148