era.dll
function ReadStrFromIni (Key, SectionName, FilePath, Res: pchar): boolean; stdcall;
function WriteStrToIni (Key, Value, SectionName, FilePath: pchar): boolean; stdcall;
Just don't forget that writable ini should be placed in real Data/Maps/etc folder, not in mods one. If you are planning to use ini only for reading then you can place it in Mods\ModName folder.