Copyright (C) 2000-2012 |
GNU Info (g77-300.info)f2c Skeletons and PrototypesGenerating Skeletons and Prototypes with `f2c' ---------------------------------------------- A simple and foolproof way to write `g77'-callable C routines--e.g. to interface with an existing library--is to write a file (named, for example, `fred.f') of dummy Fortran skeletons comprising just the declaration of the routine(s) and dummy arguments plus `END' statements. Then run `f2c' on file `fred.f' to produce `fred.c' into which you can edit useful code, confident the calling sequence is correct, at least. (There are some errors otherwise commonly made in generating C interfaces with `f2c' conventions, such as not using `doublereal' as the return type of a `REAL' `FUNCTION'.) `f2c' also can help with calling Fortran from C, using its `-P' option to generate C prototypes appropriate for calling the Fortran.(1) If the Fortran code containing any routines to be called from C is in file `joe.f', use the command `f2c -P joe.f' to generate the file `joe.P' containing prototype information. `#include' this in the C which has to call the Fortran routines to make sure you get it right. Note: Arrays (DIMENSION), for information on the differences between the way Fortran (including compilers like `g77') and C handle arrays. ---------- Footnotes ---------- (1) The files generated like this can also be used for inter-unit consistency checking of dummy and actual arguments, although the `ftnchek' tool from `ftp://ftp.netlib.org/fortran' or `ftp://ftp.dsm.fordham.edu' is probably better for this purpose. automatically generated by info2www version 1.2.2.9 |