Add a new function.
arg1 The type name of the function.
arg1
arg2 The return type.
arg2
[arg3] Calling convention, choose between cdecl, stdcall, thiscall and delphi.
[arg3]
cdecl
stdcall
thiscall
delphi
[arg4] Set to nonzero to mark this function as noreturn.
[arg4]
noreturn
This command does not set any result variables.