https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92720
--- Comment #6 from joseph at codesourcery dot com <joseph at codesourcery dot
com> ---
For the documentation of implementation-defined preprocessor behavior (as
required to be documented by a C implementation for anything the C
standard says is implementation-defined; in this case, where C11 6.10.2#2
and #3 refer to "How the places are specified or the header identified is
implementation-defined." and "searched for in an implementation-defined
manner"), see cpp.texi. It says:
@item Source file inclusion.
For a discussion on how the preprocessor locates header files,
@ref{Include Operation}.
In turn, that section "Include Operation" has more details. It doesn't
mention includes with an absolute path, but I think that's because the
general concept of resolving a path relative to a directory, and how that
handles absolute paths, is one for the underlying operating system, not
for any particular application running on that operating system.
