EMC -- "Emacs Make Compile" (or "Emacs Master of Ceremonies")

Invoking a C/C++ (and other) build tool-chain from Emacs.

Marco Antoniotti See file COPYING for licensing and copyright information.

DESCRIPTION

The standard Emacs compile machinery is mostly designed for interactive use, but nowadays, for C/C++ at least, build systems and different platforms make the process quite a bit more complicated. Moreover, it is often desirable to have a slightly higher level API to programmatically invoke a build system.

The goal of this library is to hide some of these details for Unix (Linux), Mac OS and Windows. The EMC (emc) library interfaces to make and nmake building setups and to cmake.

The supported Makefile combinations are:

Unix/Linux	Mac OS	Windows (10/11)
make	make	nmake
executable	executable	executable: .exe
library: .a .so	library: .a .dylib	library: .obj .dll

On Windows EMC assumes the installation of Microsoft Visual Studio (Community -- provisions are made to handle the Enterprise or other versions, but they are untested). MSYS2 will be added in the future, but it will mostly look like UNIX.

There are three main emc commands: emc-run, emc-make, and emc-cmake. emc-run is the most generic command and allows to select the build system. emc-make and emc-cmake assume instead make or nmake, and cmake respectively.

Invoking the command emc-run will use the emc-*default-build-system* (defaulting to :make) on the current platform supplying hopefully reasonable defaults. E.g.,

	M-x emc-run

or

	(emc-run)

from ELisp code, will usually result in a call to

	make -f Makefile

on UN*X platforms.

make

All in all, the easiest way to use this library is to invoke the emc-make command, which invokes the underlying build system (at the time of this writing either make or nmake); e.g., the call:

	M-x emc-make

or

	(emc-make)

from ELisp code, calls compile after having constructed a platform dependent "make" command. On MacOS and Linux/UNIX system this defaults to:

	make -f Makefile

On Windows with MSVC this defaults to (assuming MSVC is installed on drive :C)

	(C:\Path\To\MSVC\...\vcvars64.bat) & nmake /F Makefile

The emc package gives you several knobs to customize your environment, especially on Windows, where things are more complicated. Please refer to the emc-make function for an initial set of arguments you can use. E.g., on Linux/UNIX the call

	(emc-make :makefile "FooBar.mk" :build-dir "foobar-build")

will result in a call to make such as:

	cd foobar-build ; make -f Foobar.mk

as a result compile will do the right thing by intercepting the cd in the string (the directory name is actually fully expanded by EMC).

All commands in EMC can be invoked with a prefix, which will enter a more complex interactive session asking to manually fill in many parameters.

	C-u M-x emc-make

will ask you for the Makefile name, the "build directory", the "source directory", the make "targets" and so on.

cmake

To invoke cmake the relevant function is emc-cmake which takes the following "sub-commands" (the <bindir> below is to be interpreted in the cmake sense).

1. setup: which is equivalent to cmake <srcdir> issued in a binary directory.
2. build: which is equivalent to cmake --build <bindir>.
3. install: which is equivalent to cmake --install <bindir>.
4. uninstall: which currently has no cmake equivalent.
5. clean: equivalent to cmake --build <bindir> -t clean.
6. fresh: equivalent to cmake --fresh <bindir>.

As for emc-make, you can invoke the emc-cmake command either as
M-x emc-make or C-u M-x emc-cmake. In the first case EMC will assume that most parameters are already set; in the second case, EMC will ask for each parameter needed by the sub-command.

Other Commands

You can use the emc-run command which will ask you which sub-command to use. Again, if you prefix it with C-u, it will ask you for several other variables, including the choice of build system (which, for the time being, is either make, or cmake).

Other commands (and functions) you can use correspond to `cmake' sub commands.

1. emc-setup: which is equivalent to cmake <srcdir> issued in a binary directory and to a make setup issued in the appropriate directory as well. Note that this command usually does not mean much in a make based setup, unless the Makefile contains a setup target.
2. emc-build: which is equivalent to cmake --build <bindir> and to make issued in <bindir>; note that make will execute the recipe associated to the first target.
3. emc-install: which is equivalent to cmake --install <bindir> and to make install issued in <bindir>; note that make must provide the install target.
4. emc-uninstall: which currently has no cmake equivalent. To execute this command with cmake, CMakeLists.txt must make provisions to handle and generate the uninstall targets.
5. emc-clean: equivalent to cmake --build <bindir> -t clean, and to make clean issued in <bindir>; note that make must provide the clean target.
6. emc-fresh: equivalent to cmake --fresh <bindir>, and to make fresh. Note that this command usually does not mean much in a make based setup, unless the Makefile contains a setup target.

EMC GUI

EMC also has a simple user interface that uses Emacs widget library. It may simplify setting up the build system commands, especially because it shows the command before executing it.

You can invoke the GUI by invoking the emc-emc Emacs command (M-x emc-emc). Using it should be rather straightforward.

Documentation and Customization

EMC is decently documented in its doc-strings (it passes flycheck and flymake scrutiny; apart from a couple of minor spots where both tools cannot properly handle Common Lisp ELisp idioms).

EMC is customizable. You can find the emc Emacs custom group under Tools.

A NOTE ON FORKING

Of course you are free to fork the project subject to the current licensing scheme. However, before you do so, I ask you to consider plain old "cooperation" by asking me to become a developer. It helps keeping the entropy level at an acceptable level.

Enjoy

Marco Antoniotti, Milan, Italy, (c) 2025