Makefile and object file locations

[WebDrake]

Further to my previous question about modularizing code, when I want to compile source to object files, is there any way of determining where the object files are located?

e.g. gcc -c [all the source files] just produces objects in the present directory.

But suppose I wanted to put all the object files for a project into a special directory, how would I do that?

Many thanks,

-- Joe

 

[sedj]

The -o switch allows you to control the outputted file name/location.

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[DaveSinkula]

http://www.gnu.org/software/make/manual/html_chapter/make_4.html#SEC34

 

[WebDrake]

Thanks; but I don't quite get how to use the vpath directive (which looks like the one I need). Suppose that my libraries are all in /code/src/ and I denote by SRC the string of all source code names.

Then, I might put,

vpath %.c /code/src/

But my later compile command,

gcc -c $(SRC)

obviously only looks in the current directory. How do I alter the latter to take advantage of vpath?

Thanks,

-- Joe

 

[WebDrake]

Hmm, let's get specific. Here's my Makefile:

VPATH = /home/joecode/src/:./o/

SRC = n0.c neuR0/neuR0.c RAN.c Xhist/Xhist.c graphs/GRIDgraph.c graphs/randomgraph.c graphs/addlink.c
OBJ = n0.o neuR0.o RAN.o Xhist.o GRIDgraph.o randomgraph.o addlink.o
PROG = n0
CC = icc
FLAGS = -O3 -Ob2 -ip -ipo

$(PROG): $(OBJ)
	$(CC) $(FLAGS) $^ -o $(PROG)

$(OBJ): $(SRC)
	$(CC) $(FLAGS) -c $^
	mv *.o ./o/

The idea is that all .o files should be in the directory ./o/ before the code will try to compile them. This code produces errors---the makefile is unable to find the copied *.o files. What's wrong?

Thanks,

-- Joe