Pedantic: What Is A Source File? What Is A Header?

Question

For the purposes of this question, I am interested only in Standard-Compliant C++, not C or C++0x, and not any implementation-specific details.

Questions arise from

Answer 1

As your quotes say: a header is something included using <>, and a source file is the file being compiled, or something included using "". Exactly where the contents of these come from, and what non-standard headers are available, is up to the implementation. All the Standard specifies is what is defined if you include the standard headers.

By convention, headers are generally system-wide things, and source files are generally local to a project (for some definition of project), but the standard wisely doesn't get bogged down in anything to do with project organisation; it just gives very general definitions that are compatible with such conventions, leaving the details to the implementation and/or the user.

Nearly all of the standard deals with the program after it's been preprocessed, at which time there are no such things as source files or headers, just the translations units that your last quote defines.