4.7.3 Passing Parameters by Reference

If the parameter is passed by reference (e.g., Pascal VAR parameters), then the symbol descriptor is ‘v’ if it is in the argument list, or ‘a’ if it in a register. Other than the fact that these contain the address of the parameter rather than the parameter itself, they are identical to ‘p’ and ‘R’, respectively. I believe ‘a’ is an AIX invention; ‘v’ is supported by all stabs-using systems as far as I know.