src/tools/pginclude/README

NOTE: headerscheck and headerscheck --cplusplus are in current use,
and any problems they find should generally get fixed.  The other
scripts in this directory have not been used in some time, and have
issues.  pgrminclude in particular has a history of creating more
problems than it fixes.  Be very wary of applying their results
blindly.


pginclude
=========

These utilities help clean up #include file usage.  They should be run
in this order so that the include files have the proper includes before
the C files are tested.

pgfixinclude	change #include's to <> or ""

pgcompinclude [-v]
		report which #include files can not compile on their own

pgrminclude [-v]
		remove extra #include's

pgcheckdefines
		check for #ifdef tests on symbols defined in files that
		weren't included --- this is a necessary sanity check on
		pgrminclude

pgdefine	create macro calls for all defines in the file (used by
		the above routines)

It is also a good idea to sort the pg-specific include files in
alphabetic order.  This is best done with a text editor. Typical usage
order would be:

	pgfixinclude
	sort include references
	run multiple times:
		pgcompinclude
		pgrminclude /src/include
	pgrminclude /
	pgcheckdefines

There is a complexity when modifying /src/include.  If include file 1
includes file 2, and file 2 includes file 3, then when file 1 is
processed, it needs only file 2, not file 3.  However, if later, include
file 2 is processed, and file 3 is not needed by file 2 and is removed,
file 1 might then need to include file 3.  For this reason, the
pgcompinclude and pgrminclude /src/include steps must be run several
times until all includes compile cleanly.

Also, tests should be done with configure settings of --enable-cassert
and EXEC_BACKEND on and off.  It is also wise to test a WIN32 compile.

Another tools that does a similar task is at:

	http://code.google.com/p/include-what-you-use/

An include file visualizer script is available at:

	http://archives.postgresql.org/pgsql-hackers/2011-09/msg00311.php


headerscheck
============

This script can be run to verify that all Postgres include files meet
the project convention that they will compile "standalone", that is
with no prerequisite headers other than postgres.h (or postgres_fe.h
or c.h, as appropriate).

A small number of header files are exempted from this requirement,
and are skipped by the headerscheck script.

The easy way to run the script is to say "make -s headerscheck" in
the top-level build directory after completing a build.  You should
have included "--with-perl --with-python" in your configure options,
else you're likely to get errors about related headers not being found.

A limitation of the current script is that it doesn't know exactly which
headers are for frontend or backend; when in doubt it uses postgres.h as
prerequisite, even if postgres_fe.h or c.h would be more appropriate.
Also note that the contents of macros are not checked; this is intentional.


headerscheck --cplusplus
========================

The headerscheck in --cplusplus mode can be run to verify that all
Postgres include files meet the project convention that they will
compile as C++ code.  Although the project's coding language is C,
some people write extensions in C++, so it's helpful for include files
to be C++-clean.

A small number of header files are exempted from this requirement,
and are skipped by the script in the --cplusplus mode.

The easy way to run the script is to say "make -s cpluspluscheck" in
the top-level build directory after completing a build.  You should
have included "--with-perl --with-python" in your configure options,
else you're likely to get errors about related headers not being found.

If you are using a non-g++-compatible C++ compiler, you may need to
override the script's CXXFLAGS setting by setting a suitable environment
value.

A limitation of the current script is that it doesn't know exactly which
headers are for frontend or backend; when in doubt it uses postgres.h as
prerequisite, even if postgres_fe.h or c.h would be more appropriate.
Also note that the contents of macros are not checked; this is intentional.
