/copy members are a way to include other source members in a RPG program.
The syntax for a /copy is:
/COPY [[<library>/]<source file>,]<member>
If the library isn't specified, then the library list will be searched.
If the source file isn't specified, then the source file the program is being compiled from will be used.
For example (in the copy member):
...anything here is included regardless... /IF NOT DEFINED <somenamevalue> /DEFINE <samenamevalue> ...code here not included second time... /ENDIF ...anything here is included regardless...
Thus, if the member is copied in more than once, the code that is in the member will only be actually included once.
To exclude the entire member when referenced a second time, you can use /EOF as follows (at the top of the copy member).
/if defined <somenamevalue> /eof /endif /define <samenamevalue> ...code here not included second time...