DLL Deity since (v4.0) had support for DDE communication. This allows plugins to send strings to Hackman, which will be interpreted as though they are DDE commands. In order for you plugin to be able to utilize this, it must have a ExecutePlugin() function that accepts a SFUNCTIONS data structure. In the SFUNCTIONS data structure, there is a function pointer that points to a function contained within Hackman. This function pointer can be called like so:
SREGFUNCTIONS *myVariables; myVariables->PipeDDE(SysAllocString(OLESTR( "COMMAND TO SEND" )) );
You will notice that we use SysAllocString to allocate memory for the string that you are going to send. It is very important that you use it. Also, it is very important that you use OLESTR to convert your string. (It will be garbled if you don't!)