1 The Parameter Subsystem

The Starlink parameter system interface library, PAR (see SUN/114), provides an interface between application programs and an underlying system for handling program parameters.

The current underlying parameter subsystem allows parameters to be obtained from a number of different sources such as the user (via prompts) or values generated by other applications. Facilities are also provided for dynamic generation of default values and value limit checking. Programs may also save parameter values for use in later invocations or by other programs.

The system is implemented by five libraries in the PCS package.

SUBPAR
The top level of the underlying parameter system. Many of the basic PAR subroutines are almost straight-through calls to the corresponding SUBPAR subroutines.
PARSECON
Parsing of the interface files associated with SUBPAR. The package also includes the interface file compiler, COMPIFL.
LEX
A lexical analyser used by SUBPAR in analysing command lines etc.
STRING
Fortran string manipulation subroutines. These subroutines are also used by software items outside the parameter system, but the library has no published interface.
MISC
Miscellaneous routines which do not fit into other libraries. Two handle terminal I/O for programs running directly from a Unix shell and others provide a Fortran interface into the C library for platforms (notably Linux) which do not include them as part of the system.