Make: multiple files to GCC

Hi,

In using Make, I would like to pass more than one C file,
that needs to 
be compiled, to gcc.  The current default is to invoke gcc
with one file 
to be compiled, then invoke gcc again.

Given:

my_executable.exe : file_a.o file_b.o file_c.o file_d.o

file_a.o : file_a.c file_a.h

file_b.o : file_b.c file_b.h

file_c.o : file_c.c file_c.h

file_d.o : file_d.c file_d.h

In the above scenario, if all the '.o' file are deleted,
the gcc 
compiler will be invoked four times, once for each file.

I would like to invoke gcc once with four files on the
command line:
   gcc -c file_a.c file_b.c file_c.c file_d.c

This will speed up my build process by reducing the number
of times gcc 
is executed.  I often have to rebuild the project or all the
modules in 
a project (due to header file changes).

-- 
Thomas Matthews

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Thomas Matthews <Thomas_Hates_Spamcox.network> wrote:
> file_a.o : file_a.c file_a.h
>
> file_b.o : file_b.c file_b.h
>
> file_c.o : file_c.c file_c.h
>
> file_d.o : file_d.c file_d.h
>
> In the above scenario, if all the '.o' file are
deleted, the gcc 
> compiler will be invoked four times, once for each
file.

You can do this:
file_a.o file_b.o file_c.o file_d.o: \
  file_a.c file_b.c file_c.c file_d.c \
  file_a.h file_b.h file_c.h file_d.h
	gcc -c file_a.c file_b.c file_c.c file_d.c

The downside this way is that all four files will be
recompiled even
if only one is out of date.  You should probably measure the
build
time for each of the two Makefiles, and in each situation
(full
rebuild vs. updating one file) to see which is better
overall.


paul


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