I just made a small update to the mbLIbrary on Github.
I add the function WAPIGetCommandLine() to the WinAPI.def file. This lets you grab the Command Line parameters used to start the current MapInfo Pro Session.
This could be used to pass parameters to your MapBasic application on launch
Get the mbLibrary MapBasic modules here ((or just the WINAPI.def): https://github.com/PeterHorsbollMoller/mbLibrary
Do note that this specific def file comes in a couple flavours: one for anything before 12.5.1, one for anything after 12.5.1 and one for anything after 15.2.2.