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问题:
Please note that this is not a duplicate of the other questions named generic makefile.
I have followed all of the instructions on other questions about generic makefiles, and this is the code I have come up with from that:
CFLAGS = -c CC = cc SOURCES = $(wildcard *.cc) OBJECTS = $(patsubst %.cc,%.o,%(SOURCES)) EXEC = run all: build clean build: $(OBJECTS) $(CC) $(OBJECTS) -o $(EXEC) %.o: %.cc $(CC) $(CFLAGS) $< clean: rm *.o
However, when I execute make with a file called test.cc in my directory, it gives me the followig error:
cc -o run cc: error: no input files *** Error code 1 Stop. make: stopped in /somewhere
Please note that I am on FreeBSD and the make and cc commands are the ones which come with the OS.
回答1:
The lines
SOURCES = $(wildcard *.cc) OBJECTS = $(patsubst %.cc,%.o,%(SOURCES))
are GNU make syntax, not understood by FreeBSD's make, which has its own dialect (specifically $(wildcard) and $(patsubst)). If you need to write makefiles portable to many systems, either require gmake to exist and use GNUmakefiles, or stick to the features of POSIX make.
You can install GNU make (gmake) on FreeBSD with
cd /usr/ports/devel/gmake make install clean
回答2:
make on FreeBSD is different from GMake (make command on most linux systems), and those features require GMake. Run the command gmake instead.
I am not familiar with exactly which features require GMake.
回答3:
In FreeBSD's make, you can do it like this:
SOURCES!= ls *.cc OBJECTS = ${SOURCES:.cc=.o}
The first line uses a variable assignment modifier. Expand the value and pass it to the shell for execution and assign the result to the variable. Any newlines in the result are replaced with spaces. This is a very powerfull mechanism. You should e.g. use find instead of ls to also search in subdirectories;
SOURCES!= find . -type f -name '*.cc'
The second line uses a variable modifier to perform AT&T System V UNIX style variable substitution. It replaces the suffix .cc with the .o suffix.
