Thank you for your quick response. I follow your instructions and I did several experiments but I cannot get my problem solved. These are the experiments performed:
First experiment: loading "mod_spatialite.dll":
I wrote this line in the sqlite3 command-line tool:
SELECT load_extension('mod_spatialite.dll');
As a result of this sentence I did not get any error message. It is interesting to note that the file "mod_spatialite.dll" was in the same folder than "sqlite3.exe". Nevertheless, I could not do that in LabVIEW, also after copying the DLL file in the same folder than the VI file.
Second experiment: loading "mod_spatialite.dll" with its absolute path:
I wrote this line in the sqlite3 command-line tool:
SELECT load_extension('D:\Program Files (x86)\National Instruments\LabVIEW 2019\VMM.lib\mod_spatialite-4.3.0a-win-amd64\mod_spatialite.dll');
As a result of this sentence I get this error message: "Error: No se puede encontrar el módulo especificado" (in English it can be translated as "Cannot find the specified module"). It is insteresting to note that "'D:\Program Files (x86)\National Instruments\LabVIEW 2019\VMM.lib\mod_spatialite-4.3.0a-win-amd64\" is the absolute path of the location of the "mod_spatialite.dll" file.
Third experiment: loading "extension-functions.dll" with its absolute path:
I wrote this line in the sqlite3 command-line tool:
SELECT load_extension('D:\Program Files (x86)\National Instruments\LabVIEW 2019\vi.lib\drjdpowell\SQLite Library\SQL Connection\extension-functions.dll');
As a result of this sentence I get the same error message: "Error: No se puede encontrar el módulo especificado". It is insteresting to note that:
"'D:\Program Files (x86)\National Instruments\LabVIEW 2019\vi.lib\drjdpowell\SQLite Library\SQL Connection\" is the absolute path of the location of the "extension_functions.dll" file.
This sentence worked properly in the LabVIEW code shown in my previous post when selecting this path in the "dll File Path" control.
Fourth experiment: loading "extension-functions.dll" without its absolute path:
The last experiment consisted on trying to do not get an error message by repeating the procedure employed in the first experiment. To do so, I moved the "extension-functions.dll" file to the same folder than the "mod_spatialite.dll" and the "slqite3.exe" files. After that, I wrote this line in the sqlite3 command-line tool:
SELECT load_extension('extension_functions.dll');
As a result of this sentence I get again the same error message: "Error: No se puede encontrar el módulo especificado".
To sum up, the description of the error obtained is "Error: No se puede encontrar el módulo especificado" (in English it can be translated as "Cannot find the specified module"). Moreover, in the first experiment I was able to load the "mod_spatialite.dll" file without error, but it did not worked in LabVIEW. Finally, in the fourth experiment I get an error message even with a sentence that worked in LabVIEW.
Thank you in advance for your help!
Víctor