NAG Fortran Compiler, Release 7.2: File Types

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## 2.3 File Types

A file ending in ‘`.f90`’ or ‘`.f95`’ is taken to be a Fortran free-form source file, a file ending in ‘`.f`’, ‘`.for`’ or ‘`.ftn`’ is taken to be a Fortran fixed-form source file; these assumptions can be overridden with the -fixed or -free option. A file ending in ‘`.ff90`’ or ‘`.ff95`’ is taken to be a free-form file requiring preprocessing by fpp, and a file ending in ‘`.ff`’ is taken to be a fixed-form file requiring preprocessing by fpp. On Unix, a file ending in ‘`.F90`’ or ‘`.F95`’ is taken to be a free-form file requiring preprocessing by fpp, and a file ending in ‘`.F`’ is taken to be a fixed-form files requiring preprocessing by fpp. (Note that on MacOS and Windows, the file system is not case-sensitive so uppercase and lowercase letters are equivalent in filenames including in the suffixes.)

If a filename without a suffix is provided nagfor will look for a file with the suffix ‘`.f95`’, and if that does not exist, the suffix ‘`.f90`’.

A file ending in ‘`.c`’ is taken to be a C source file. In the =compiler mode, this is assumed to be the output from the compiler with the -S option, and the C compiler is passed -D and -I options suitable for compiling such a file. In the =C mode, it is assumed to be a file for the companion processor; no -D is passed, and only -I options specified by the user. In both cases, options are passed to the C compiler according to the ABI and compatibility mode options.

Non-intrinsic modules, `INCLUDE` files and `#include` files are expected to exist in the current working directory or in a directory named by an -I option.