A.1 Routine Definitions
Routines which can be used in an IDL program can be defined in
several places:
- Builtin routines are defined inside IDL itself. The source code
of such routines is not available, but instead are learned about through
the IDL documentation.
- Routines which are part of the current program, are defined in a
file explicitly compiled by the user. This file may or may not be
located on the IDL search path.
- Library routines are defined in files located on IDL’s search
path. When a library routine is called for the first time, IDL will
find the source file and compile it dynamically. A special sub-category
of library routines are the system routines distributed with IDL,
and usually available in the lib subdirectory of the IDL
distribution.
- External routines written in other languages (like Fortran or C) can be
called with
CALL_EXTERNAL, linked into IDL via LINKIMAGE,
or included as dynamically loaded modules (DLMs). Currently IDLWAVE
cannot provide routine info and completion for such external routines,
except by querying the Shell for calling information (DLMs only).