C and C++ have a plethora of different functions to copy strings, while Pascal has just 1.
C and C++ have all kinds of unbounded arrays, even for parameter passing, that Pascal lacks.
Due to the rich macros, you can freely change the meaning of most things and completely change the syntax of C and C++. Pascal doesn't have that, either.
Actually, there are a lot of things you can do in C and C++ that you cannot in Pascal, if you strictly look at the effects. And both cannot do half the things you can accomplish with assembly code. Then again, if you look at the results instead, you see that most of the things that are left out aren't very useful to begin with.
So, is there a program you can write in C or C++, that you cannot in (Free) Pascal? Certainly. There are platforms that aren't supported. But then again, there are also platforms that run Free Pascal applications that have no C and/or C++ compiler. And there are platforms that have neither.
Otherwise, use what you like best, it doesn't matter.