SmallCppProjectMakefile

This Makefile is suitable for building small C++ projects. It requires very little extra configuration. It assumes a GNU C++ compiler, and GNU Make: Make manual It was written for Linux, but has been reported to work on Macs and under MinGW64. It does not seem to break when make is told to run parallel jobs.

Most basic use:

Put Makefile and sources in one directory and there issue the command:

make

To remove all the generated files (which should seldom be necessary):

make clean

Default behavior:

This Makefile causes make to want to build programs, or if there are no program sources, to build a convenience library. To do so, the following steps are taken.

• Flexc++ will be called on any scanner specification files.
• Bisonc++ will be called on any parser specification files (grammars).
• C++ source files and internal headers will be preprocessed in order to determine their include dependencies. stackoverflow on internal headers
• If included anywhere, C++ internal header files will be precompiled.
• C++ source files will be compiled into object files.
• A convenience library will be composed of all non-program object files.
• Program object files (detected by grepping the source for a main function) will be linked against the convenience library to become executable programs.

Because the Makefile detects which files include which others, updating a header file will cause all source files that (indirectly) include it to be remade. On one hand, this consumes time. On the other hand it saves time by keeping sources and headers in sync, so make clean should seldom have to be run.

Influencing the Makefile:

The Makefile accepts the usual variables (CXX, CXXFLAGS, CPPFLAGS, LDFLAGS etc.) as well as FLEXCXX (defaults to: flexc++) and BISONCXX (defaults to: bisonc++) These can be set in the usual ways: How variables get their values

They can also be set in a file hooks.mk, which if it exists, will be included. Extensions can be set there too, though it should seldom be necessary, as they auto-adapt to files found.

CXX_SOURCE_EXTENSION (defaults to: cc)
CXX_HEADER_EXTENSION (defaults to: hh)
CXX_INTERNAL_HEADER_EXTENSION (defaults to: ih)
FLEXCXX_SCANNERSPEC_EXTENSION (defaults to: fc++)
BISONCXX_PARSERSPEC_EXTENSION (defaults to: bc++)

When setting extensions, do NOT include the dot in the extension! DEPDIR (defaults to: generated_deps) can also be set but is best left alone.

Some variables change the behaviour more extensively:

VERBOSE=yes causes commands in recipes to be echoed.
DEP=no      causes dependency analysis to be skipped.
PCH=no      prevents precompiled headers from being built,
            but not necessarily from being used if they exist.

Note that without analyzing dependencies, Make will not know which source file includes which internal header, so it will not create or update precompiled headers.

Creating files from templates:

Some files can be created from templates integrated in this Makefile. E.g.:

mkdir mc
make mc/myclass.hh
make mc/myclass.ih
make mc/ctor1.cc
mkdir parser
make parser/grammar.bc++
make parser/tokenizer.fc++
make myprog.cc:program

The command for creating a program source differs because it shares its file extension with non-program sources. To make header files, the uuid utility must be present. It is convenient to create the header first, because the template for the internal header will subsequently find and include it. The template for source files will find the internal header in turn.

Other files

The other files are just there to demonstrate the purpose of a Makefile. The .ih-files are internal headers, as explained in comment.