4.2.2 Example – Configuring a tool called via make

In this example we will add support for C files syntax checked by gcc called via make.

We're not required to write any new functions, as Flymake already has functions for make. We just add a new entry to the flymake-allowed-file-name-masks:

     (setq flymake-allowed-file-name-masks
           (cons '(".+\\.c$"
                   flymake-simple-make-init
                   flymake-simple-cleanup
                   flymake-get-real-file-name)
                 flymake-allowed-file-name-masks))

flymake-simple-make-init builds the following make command line:

     (list "make"
           (list "-s" "-C"
                 base-dir
                 (concat "CHK_SOURCES=" source)
                 "SYNTAX_CHECK_MODE=1"
                 "check-syntax"))

base-dir is a directory containing Makefile, see Locating the buildfile.

Thus, Makefile must contain the check-syntax target. In our case this target might look like this:

check-syntax:
        gcc -o nul -S ${CHK_SOURCES}

The format of error messages reported by gcc is already supported by Flymake, so we don't have to add a new entry to flymake-err-line-patterns.