Re: Using " rather than < for header files in Emacs

[Paul Eggert <eggert@cs.ucla.edu>]

Herring, Davis wrote:
> It is defined by C (don't know as of which version off hand) that #include"x" can find what #include<x> finds (but may find something else first).

Yes, a portable program can't assume that "..." will find files that <...> 
won't. In some C compilers, "..." looks in the working directory that the 
compiler is run in; in POSIX-compatible compilers (including GCC) "..." will 
first look in the directory containing the source file that has the "..."; in 
other C compilers (including Microsoft) "..." will also search in the 
directories of currently opened include files; and I assume there are other 
possibilities.

In theory, the "..." form could lead to including the wrong file. In practice, 
the way Emacs does it is harmless, but why add risk by using "..." more often?

(There was a reason in GCC before 3.0 to prefer angle brackets or double quotes, 
depending on whether you wanted -MM to generate dependency information, but that 
reason is obsolescent now.)