Moving the variable data to the map

Having obtained storage for your map, established the relationship of the map structure to the storage, and initialized, you are finally ready to create your output. There are two parts to it: the data itself and its display attributes. Firstly, we explain to you about the data, and then we explain to about the attributes.

In the typical case, an output display consists of some constant or default data (provided by the physical map) and some variable data (provided by the program). For each field that you want to supply by program, you move the data into the field in the symbolic map whose name is the name assigned in the map suffixed by the letter O. See the code in A BMS output example for an example.

If you do not supply a value for a field (that is, you leave it null, as initialized), BMS ordinarily uses the initial value assigned in the map, if any. Constants (that is, fields without names) also get the initial values specified in the map. However, the DATAONLY and MAPONLY options on the SEND MAP command modify the way in which program and map data are merged; we explain these options in Merging the symbolic and physical maps and summarize the exact rules in Building the output screen.