> csoundCompile use argc and argv and this are meant from command line

It means an array of `argc' strings where the first string is the
name of the command. If you want you can get them from the command
line but it is not mandatory.

> Using Lua (or Python) i have a function setCommand(string command), is there
> somethings similar in c?

There is a `setCommand' in c++ (csound5/interfaces/CsoundFile.cpp)
but not in c. Continue the C experience with `malloc' and `free'.
Useful functions for the operations with the strings are

  man 3 string