Re: clear command in makefile..

[Dave Seaman]

On 3 Jul 2006 03:24:36 -0700, silversurfer wrote:
> so there is no possibility to do this?

You can make your primary target depend on a phony target that clears the
screen.

$ cat Makefile
all:    clearscreen main

main:main.o $(ADDOBJS)
        @g++ -o main $(LDFLAGS) $+

.PHONY:         clearscreen

clearscreen:
        clear

$ make -n all
clear
g++    -c -o main.o main.cc
g++ -o main  main.o



> Dave Seaman wrote:
>> On 1 Jul 2006 09:37:59 -0700, silversurfer wrote:
>> > Hello world,
>> > I was just wondering why the clear-line in my Makefile does not work:
>>
>> > main:main.o $(ADDOBJS)
>> >          clear
>> >          @g++ -o main $(LDFLAGS) $+
>>
>>
>>
>> > As far as I understood it, it should be possible to add multiple
>> > shell-commands.. Nevertheless, this does compile the files, but the
>> > 'clear' before does not work..
>>
>> > Anyone knows why?
>>
>> > PS I would like to use this because I like having a clean screen with
>> > the actual errors on it.. for me, it is easier... ;)
>>
>> The "clear" command actually does work, but it's not necessarily the
>> first thing that gets generated when you run "make".  It only gets
>> generated when that particular rule is applied, and that rule is not what
>> causes the program to be compiled.
>>
>> You can type "make -n" to have the generated sequence of commands echoed
>> to the screen without being executed.
>>
>> If you have, say, a main.cc file plus a Makefile containing exactly those
>> three lines quoted above, you will see the following:
>>
>> $ make -n
>> g++    -c -o main.o main.cc
>> clear
>> g++ -o main  main.o
>>
>>
>> The reason for this is that you didn't actually specify a compile command
>> in your Makefile, but only a link command.  You said "main" depends on
>> "main.o", but you didn't give a rule for generating "main.o".  The "make"
>> program supplied the compile command for you from its implicit rulebase,
>> thus generating "main.o" for you.  Once the prerequisite (main.o) was
>> satisfied, "make" was able to proceed by applying your rule for the
>> link step.
>>
>>
>> --
>> Dave Seaman
>> U.S. Court of Appeals to review three issues
>> concerning case of Mumia Abu-Jamal.
>> <http://www.mumia2000.org/>



-- 
Dave Seaman
U.S. Court of Appeals to review three issues 
concerning case of Mumia Abu-Jamal.
<http://www.mumia2000.org/>