Since this is related to the IBM i platform, you may want to ask the question in IBM i - Home - IBM Power Community
Here is feedback from what I asked your question in an internally IBM forum:
I might need more information to answer authoritatively. There is an option to the compiler called SRCFILE() that would look like this on the command line:
CRTCPPMOD SRCFILE(LIB/FILE)
The option allows the user to specify the library and source physical file in the data management file system that contains the source code they are trying to build. The option is described here:
https://www.ibm.com/docs/en/i/7.5?topic=options-srcfileIBM i has two primary ways to access files, the Integrated File System (IFS) and the Data Management file system. This section in the Programmer's Guide might help explain how source code ends up in a DM file.
https://www.ibm.com/docs/en/i/7.5?topic=program-entering-source-statements#entering_source------------------------------
JC Yao
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