Use this program to return a string value. The argument of the macro should be a zero terminated string.
The macro allocates the return string, copies the content of the string to the allocated space and returns from the function using the macro with no error (COMMAND_ERROR_SUCCESS).
If the return value can not be allocated the macro returns with COMMAND_ERROR_MEMORY_LOW.
If the argument is NULL the macro will return the BASIC value undef.
The macro evaluates its argument twice.