linux QT undefined symbol: g_main_context_default

This error occurs when the application is trying to use a symbol that is not defined. In this case, it is trying to use the symbol "g_main_context_default" which is not defined in the library or the system.

To fix this error, you can try the following solutions:

1. Check if the required library is installed: Make sure that the library that contains the symbol is installed on your system. If it is not installed, install it using the package manager of your Linux distribution.

2. Check the library path: Check if the library path is set correctly. If the library is installed in a non-standard location, you need to set the LD_LIBRARY_PATH environment variable to the path of the library.

3. Rebuild the application: If the library is installed and the path is set correctly but the error still persists, try rebuilding the application. This may fix the issue if there was a problem with the build process.

4. Upgrade the library: If the library is outdated, try upgrading it to the latest version. This may fix the issue if the symbol was added in a later version of the library.