Make file questions

[Sim085]

I have observed some anomalies in my make files so I am trying to replicate the problems in smaller problems to understand what I am doing wrong.

The first problem I have is that when I do a change make will build the object file but does not recompile the executable.

So I have created a simple project with just a main.c which prints hello world and this is my make file;

CC=vc +aos68k
COPT = 
LIBS = -lamiga -lauto

all: App

%.o : %.c
    vc -c -o $@ $<

App : main.o
    vc $^ -o $@ $(LIBS)

clean:
    -delete main.o APP

When I build the first time the main object file is built and the executable file is built. But if I do a change in main.c then only the main object file is re-built. The executable does not get rebuilt.

However I have other make files where the executable is re-built each time and the only difference is I moved the source files in /src and the build files in /build and the executable file in /bin. Just doing one of these does not seem to work, it seems the three of them needs to be done for the executable to be re-built. After this change, however, even without any changes the executable is rebuilt each time. Here is the second make file;

CC=vc +aos68k
COPT = 
LIBS = -lamiga -lauto

all: folder App

folder: 
	-makedir build
	-makedir bin

build/%.o : src/%.c
	vc -c -o $@ $<

App : build/main.o
	vc $^ -o bin/$@ $(LIBS)

clean:
	-delete build/main.o bin/App

Is this normal? Or there is something wrong with my make file?

[thomas]

The first example works perfectly for me. App is rebuilt whenever I change main.c.

Make sure the system clock is running properly. If a new .o file is older than the existing App file, it will not be relinked. This often happens if the source directory is on a NAS server (connected via SMBFS) and the time zone is not set up correctly. Or if the system clock is running too fast and after a reboot time has been set back. Or if there is no RTC and after a reboot the clock has been set back to a very old date.

Also make sure that all file names are written with proper case as given in the makefile. Names in makefiles are case sensitive.

Finally make sure that dependencies are specified correctly. For example a mistake I often make is

main.c: something.h

instead of

main.o: something.h

[Sim085]

Good to know the script should be good.



I am using FS-UAE on Mac. Will try the same script on WinUAE when I have access to my Windows machine.

Originally Posted by thomas

The first example works perfectly for me. App is rebuilt whenever I change main.c.

Make sure the system clock is running properly. If a new .o file is older than the existing App file, it will not be relinked. This often happens if the source directory is on a NAS server (connected via SMBFS) and the time zone is not set up correctly. Or if the system clock is running too fast and after a reboot time has been set back. Or if there is no RTC and after a reboot the clock has been set back to a very old date.

Also make sure that all file names are written with proper case as given in the makefile. Names in makefiles are case sensitive.

Finally make sure that dependencies are specified correctly. For example a mistake I often make is

main.c: something.h

instead of

main.o: something.h