#### 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.