1. Libraries not found at runtime

You may receive the following error when compiling and running SDK examples on Windows

Could not find/load native library (libopenalpr.dll)
OpenALPR was not properly initialized.

This is because all the dynamically linked libraries (DLLs) are in the root folder of the SDK download and NOT on the path that your .exe file is searching. To fix the issue, you can either

  • Modify your system %PATH% variable to include the root SDK folder (recommended)
  • Copy all of the DLLs from the root SDK folder to the folder containing your .exe

Note since this is a runtime linkage, you will not need to recompile for the change to take effect

2. Licensing check failed

You must have a valid key in a file named license.conf that is either in the same folder as your .exe or on the system %PATH% (see above). If you have already purchased a key, you can access it by logging in to your account at https://license.openalpr.com. To request a 2-week evaluation license, please visit https://license.openalpr.com/evalrequest.

3. Config file does not exist

When initializing an Alpr instance, you must specify the path to an openalpr.conf file. The default in most example programs is to check the current folder (where the .exe was run from). You can either copy the configuration file from the root SDK folder to your .exe folder or modify the source code to search a different path and recompile.

4. Runtime directory does not exist (invalid country)

Similarly to the configuration file, you also need a valid path to the runtime_data directory. Most examples default to searching the current folder so you can either copy the runtime folder there or modify the source code to search a different path and recompile.

If the runtime folder is correctly found but you receive an invalid country error, please check the ...\runtime_data\config folder for valid options. Each allowable country has a *.conf file whose filename can be passed as a string to initialize the Alpr instance (i.e. ar, au, br, cn, etc).