National Instruments 320685D-01 Resolving References from Modules Loaded at Run-Time, Resolving References to the LabWindows/CVI Run-Time Engine , Resolving References to Symbols Not in Run-Time Engine

Chapter 3 Windows95/NT Compiler/Linker Issues

LabWindows/CVI Programmer Reference Manual 3-12

National Instruments Corporation

4. Include this object file in the external compiler project you use to create the DLL.

5. You must call InitCVIRTE and CloseCVIRTE in your DLLMain function. Refer to the

Calling InitCVIRTE and CloseCVIRTE section later in this chapter.

Resolving References from Modules Loaded at Run-Time

Note This section does not apply unless you use LoadExternalModule to load object

or static library files.

Unlike DLLs, object and static library files can contain unresolved references. If you call

LoadExternalModule to load an object or static library file at run time, the Utility

Library must resolve those references using function and variable symbols from the

LabWindows/CVI Run-time Engine, from the executable, or from previously loaded run-time

modules. A table of these symbols must be available in the executable. When you link your

program in LabWindows/CVI, LabWindows/CVI automati cally includes a symbol table. This

is true whether you run your program in the LabWindows/CVI developmen t environment or

as a standalone executable.

When you link your program in an external compiler, the external compiler does not make

such a table available to the Utility Library. LabWindows/CVI provides ways to help you

create the symbol table easily.

Resolving References to the LabWindows/CVI Run-Time Engine

LabWindows/CVI makes available two object files that contain symbol table information for

the LabWindows/CVI libraries that are in Run-time Engine DLLs:

• Include cvi\extlib\refsym.obj in your external compiler project if your run-time

modules refer to any symbols in the User Interface, Formatting and I/O, RS-232, DDE,

TCP, or Utility Library.

• Include cvi\extlib\arefsym.obj in your external compi ler project if your run- time

modules refer to any symbols in the ANSI C library. If you ha ve to use this obj ect file and

you use Borland C/C++ to create your executable, you must choose Static Linking for the

Standard Libraries. In the Borland C/C++ IDE, you can do this in the New Target and

Target Expert dialog boxes.

Resolving References to Symbols Not in Run-Time Engine

If your run-time modules refer to any other symbols from your executable, you must use

LabWindows/CVI to generate an object file that contains a table of those symbols. Create an

include file that contains complete declarations of all the symbols your run-time modules

reference from the executable. The include file can contain nested #include statements and

can contain executable symbols that your run-time modules do not refer to. If your run-time