Chapter 2 Using Loadable Compiled Modules
LabWindows/CVI Programmer Reference Manual 2-2
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National Instruments Corporation
Advantages and Disadvantages of Using Loadable Compiled Modules inLabWindows/CVI
Using compiled modules in LabWindows/CVI has the following advantages:
Compiled modules run faster than source modules. Compiled modules do not contain the
debugging and user protection code LabWindows/CVI generates when it compiles
source modules. Compiled modules you generate in external compilers can run faster
because of optimization.
LabWindows/CVI recompiles the source modules in a project each time you open the
project. Also, if an instrument driver program file is a source module, LabWindows/CVI
recompiles it each time you load the instrument driver. LabWindows/CVI does not
recompile compiled modules when you open a project or load an instrument driver.
In standalone executables, you can dynamically load compiled modules but not source
modules.
You can install compiled modules, but not source modules, into the Library menu.
You can provide libraries for other developers without giving them access to your source
code.
Using compiled modules in LabWindows/CVI has the following disadvantages:
You cannot debug compiled modules. Because compiled modules do not contain any
debugging information, you cannot set breakpoints or view variable values.
Compiled modules do not include run-time error checking or user protection.
Using a Loadable Compiled Module as an Instrument Driver ProgramFile
An instrument driver is a set of high-level functions with graphical function panels to make
programming easier. It encapsulates many low-level operations, such as data formatting and
GPIB, RS-232, and VXI communication, into intuitive, high-level functions. An instrument
driver usually controls a physical instrument, but it also can be a software utility. The Using
Instrument Drivers and Instrument Menu sections of Chapter 3, Project Window, of the
LabWindows/CVI User Manual describe how to use instrument drivers.
To develop and debug an instrument driver, load its program file into LabWindows/CVI as a
source file. After you finish debugging it, you can compile the program file into an object file
or a Windows 95/NT DLL. The next time you load the instrument driver, LabWindows/CVI
loads the compiled module, which loads and runs faster that the source module.
Refer to the LabWindows/CVI Instrument Driver Developers Guide for information on how
to create an instrument driver.

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