Portability Tools.
There are a number of "operating systems support" functions that are frequently needed in programs, for which no standard interface is available. Examples of such functions are: access to the shell, access to command line arguments, access to environment variables or VMS logical names, elapsed cpu time, and so on. To have access to such functions and still maintain portability, applications frequently resort to conditional compilation, by various methods such as cpp directorives.

The following NTCC modules are of interest in code porting work:

--portlib:

PortLib -- VMS/UNIX (Fortran) Portability Library. There are a number of "operating systems support" functions that are frequently needed in programs, for which no standard interface is available. Examples of such functions are: access to the shell, access to command line arguments, access to environment variables or VMS logical names, elapsed cpu time, and so on. In UNIX terminology these are the fortran "3f" routines: system, getarg, getenv, etc. Accessing these routines requires slightly different code, depending on vendor or operating system. The portlib library provides a standardized portable interface to these routines, encapsulating the system to system variability, making it easier for the applications developer to achieve portability without the need to resort to such techniques as conditional compilation via cpp directives.

--ftoken:

Ftoken -- a set of fortran-77 portability conversion tools built on a token parsing library (ftoken). These tools are:

• fgtok: table driven token substitution tool with fortran-77 specific features.
• idecl: make implicit INTEGER and REAL declarations explicit, allowing a code to be converted to compile with IMPLICIT NONE
• cpcheck: scan a named source file for presence of macros defined in a named header file. If any of the macros occur, print "present", otherwise print "absent".
• r8real: automatically generate a REAL*8 interface to subroutines or functions which use single precision REAL arguments.

These tools are recommended for one time portability (and precision) conversions of codes. Examples of conversions: (a) change REAL and COMPLEX declarations to REAL*8 and COMPLEX*16, (b) convert all references to fortran intrinsic functions to their generic (and portable) form, (c) convert hard coded constants to D-exponent format. The module includes name substitution tables and scripts enabling automated code conversions.

--fpreproc:

A set of python scripts and ".h" files for preprocessing of Fortran 90 and Fortran 77 sources, to support conditional compilation and macro substitution, that give methods for implementing portable code from a single source.