UNIX - makefile帮助！

Question

Looking for help compiling my program below. I'm getting a "***Stop. no Targets." error when typing in limit.makefile in the compiler buffer. Ideas?

int main(int argc, char *argv[]) {
  struct rlimit limit;

  limit.rlim_cur = 60000;


limit.rlim_max = 60000;

if (setrlimit(RLIMIT_FSIZE, &limit) == -1){
    perror("Error preventing core dump, errno=%d\n", errno);
    exit(1);
  }

else {
    printf("The current core limit is %ll.\n", limit.rlim_cur);
    printf("The core max limit is %ll.\n", limit.rlim_max);
    exit(0);
  }

  if (getrlimit(RLIMIT_FSIZE, &limit) == -1){
    printf("getlimit() failed with errno=%d\n", errno);
    exit(1);
  }


}

Compile command: make -k -f limit.makefile This is what I type for the compiler buffer....still get the error though.

Makefile:

CC = /usr/bin/gcc
CFLAGS = -g -Wall -std=c99 -O2 -arch x86_64

Answer 1

Just tried that make -k -f myfile on an empty file and got your error.

If you just want it to work

CC= /usr/bin/gcc 
CFLAGS = -g -Wall -std=c99 -O2 -arch x86_64



all: test.c
    $(CC) $(CFLAGS) test.c

Note that the tab under all has to be a "real" tab.

I recommend you check out a makefile tutorial or just compile it from the command line. gcc -g -Wall -std=c99 -O2 -arch x86_64 limit.c

BTW, not sure about that -arch flag. Not valid on my Linux box.

Answer 2

Try

CC = /usr/bin/gcc
CFLAGS = -g -Wall -std=c99 -O2 -arch x86_64
OBJ = limit.o

%.o: %.c
    $(CC) -c -o $@ $< $(CFLAGS)

Answer 3

EboMike's is more sophisticated, but here's a simpler one that is guaranteed to work for your one-file project:

CC = /usr/bin/gcc
CFLAGS = -g -Wall -std=c99 -O2 -arch x86_64

limit: limit.c
    $(CC) $(CFLAGS) -o limit limit.c

You can run this with just make by itself.

Answer 4

You've not defined what the target to build is anywhere. You can do that on the command line, using the command

make -k -f limit.makefile limit

and the implicit rules of make will compile limit.c into limit . Alternatively define a target in your makefile,

CC = /usr/bin/gcc
CFLAGS = -g -Wall -std=c99 -O2 -arch x86_64
limit: limit.o

The first target will be built by default, and make knows how to compile *.c to *.o and link object files so everything else is automatic.

If you're curious, the default rules are equivalent to (in GNU make)

%.o:%.c
    $(CC) $(CPPFLAGS) $(CFLAGS) -c -o $@ $<
%:%.o
    $(CC) $(LDFLAGS) -o $@ $^ $(LDLIBS)

where $@ , $< and $^ expand to the target, first prereq and all prereqs respectively, the percent signs are wildcards for the target name.