Re: Changing the Compile-Command in C/C++ Mode

[Kevin Rodgers <ihs_4664@yahoo.com>]

Balaji V. Iyer wrote:
> Hi Everyone,
>   	I do not always use a make file and I would like the emacs (version
> 21.2.1) to modify the compile-command line to "g++ -Wall -O4 filename.c. I
> thought this script did the trick but it didn't. I do not get any syntax
> error, but when I hit the M-x compile command I still get "make -k"
> How can I fix this? If you have an alternative implementation, I am willing
> to use that too.
> 
> (function
>  	   (lambda ()
>  	     (unless (or (file-exists-p "makefile")
>  			 (file-exists-p "Makefile"))
>  	       (make-local-variable 'compile-command)
>  	       (setq compile-command
>  		     (concat "gcc -Wall -O3 -o"
> 		             (file-name-sans-extension
> (file-name-nondirectory buffer-file-name))
> 			     " "
>  			     (file-name-nondirectory buffer-file-name))))))

If that's precisely what is in your .emacs, it doesn't accomplish
anything because all you've done is define an anonymous function without
ensuring that it will ever be called.

Since that compile-command is only useful for C files, do what the doc
string for compile-command suggests:

(add-hook 'c-mode-hook (lambda () ...))

Better yet, rely on make's default rules and macros (e.g. CC and CFLAGS):

(add-hook 'c-mode-hook
           (lambda ()
             (set (make-local-variable 'compile-command)
                  (concat "make "
                          (file-name-sans-extension
                           (file-name-nondirectory buffer-file-name))))))

-- 
Kevin Rodgers