UniBasic Commands Reference - Rocket Software

CALLC
Syntax
CALLC c.sub.name [(argument1[,argument2]...)]
CALLC @var [(argument1[,argument2]...)]
Description
The UniBasic CALLC command transfers program control to an external function
(c.sub.name). The second form of the syntax calls a function whose name is stored in
a UniBasic variable (@var). The program could pass back return values in variables.
CALLC arguments can be simple variables or complex expressions, but not arrays.
CALLC can be used as a command or function.
Calling a C Program in UNIX
You must link the C program to UniData before calling it from a UniBasic program.
Perform the following procedure to prepare UniData for CALLC:
1-123 UniBasic Commands Reference
1. Write and compile the C program.
2. Define the C program call interface.
3. Build the runtime version of UniData (containing the linked C program).
4. Write, compile, and execute the UniBasic program.
For more information about this procedure, see Developing UniBasic Applications.
Calling a Function on Windows Platforms
The CALLC implementation in UniData for Windows Platforms uses the Microsoft
Windows Dynamic Link Library (DLL) facility. This facility allows separate pieces
of code to call one another without being permanently bound together. Linking
between the separate pieces is accomplished at runtime (rather than compile time)
through a DLL interface.