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Chapter 7

Creating and Distributing Standalone Executables and DLLs

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 National Instruments Corporation

7-17

LabWindows/CVI Programmer Reference Manual

Under Windows 95/NT, you cannot pass the pathname of a DLL directly into 

LoadExternalModule

. Instead, you must pass the pathname of a DLL import library. You 

can link the import library into your executable or DLL or distribute it separately and load it 
dynamically. For import libraries that you link into your executable or DLL, refer to the 

 section earlier in this chapter. For import 

libraries that you load dynamically, refer to the 

 section earlier in this chapter.

You must always distribute DLLs as separate files. The operating system finds the DLL 
associated with the loaded import library using the standard Windows DLL search algorithm. 
The search precedence is as follows.

1.

The directory from which the application loads

2.

The current working directory

3.

Under Windows 95, the Windows 

system

 directory. Under Windows NT, the Windows 

system32

 and 

system

 directories

4.

The Windows directory

5.

The directories the 

PATH

 environment variable lists

DLL files and DLL path files are never linked into the executable, so you must distribute them 
as separate files.

Your executable can call 

LoadExternalModule

 directly on a DLL or DLL path file only if 

you include the DLL or DLL path file in the project. When you select Create Standalone 
Executable File, LabWindows/CVI automatically creates the DLL glue code and links it into 
the executable. 

Also, you can pass the DLL glue object module filename to 

LoadExternalModule

. You can 

generate the DLL glue object module by opening the 

.h

file for the DLL in a Source window 

of LabWindows/CVI and selecting Generate DLL Glue Object from the Options menu. 

If you include the DLL, the DLL path file, or the DLL glue object module as a file in the 
project, you must pass 

LoadExternalModule

 a simple filename, and it uses the following 

search method to find the DLL.

1.

Look for a 

.pth

 file in the directory of the executable. The 

.pth

 file must have the same 

base name as the file you passed to 

LoadExternalModule

. If the 

.pth

 file contains an 

absolute path to the DLL, use that path to find the DLL. If the 

.pth

 file contains a simple 

filename, use the standard Windows DLL search algorithm: directory of executables, 

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