The -fullpaths option causes the compiler to specify the full path to the file when listing compilation errors and warnings.
-fullpaths
By default, errors and warnings that result from compilation specify the name of the file in which an error was found. The -fullpaths option causes the compiler to specify the full path to the file.
This compiler option is unavailable in Visual Studio and cannot be changed programmatically. It is enabled by default when compiling inside Visual Studio.