_CP_build_msg queues up arguments for _CP_out_msg. This function, in conjunction with _CP_out_msg, is equivalent to the BASIC error statement. Each parameter is first stacked with _CP_build_msg, and then output with the _CP_out_msg.
_CP_interrupt is a global C integer which contains the last D3 interrupt that occurred. This value is the same as that returned by the BASIC function system(37). It is available when linking with the D3 libraries.
_CP_pick_env sets the application to a standard D3 environment. When using this setting, all terminal input and output must be done via D3 routines only (execute, print, crt). The default environment after logging on to D3 is _CP_pick_env.
_CP_SADDR returns a standard char* pointing to the first character of the string buffer within a CPSTR structure. Because _CP_SADDR is a macro, it can be used either to the left or right side of an assignment operator.
_CP_str_alloc allocates space for a CPSTR. It is the equivalent of malloc(), but returns a CPSTR*. The expression should contain the length of the string buffer to allocate. A 0 is returned if a failure occurs.