External modules are normal modules, which
contains information about external object/library files. Currently
global variables, procedures and linked library functions.
Global variables in external files are defined with 'EDEF' keyword, with this syntax:
Syntax is completely same as with DEF. Only don't
forget that arrays are derived to pointers.
External procedures are defined in the same was as normal procedures,
but leading with 'EPROC' instead of
'PROC'. All arguments and all return types
must be defined:
EPROC <name>(<args>) [ (<result>) ]
where <name> is the external procedure
name, <args> are fully typed variable
names (names are skipped by PowerD), <result>
must be the same as in the procedure definition. If you write an
external definition of C compiled function, use LPROC
instead of EPROC keyword.
Linked library functions:
Linked library functions are defined in same way as external procedures,
but leading with 'LPROC' instead of 'EPROC'.