Reputation: 1465
I have 3 functions separated in .c files and the main.c I would like to make the make file, I wrote in the file:
# Indicate that the compiler is the gcc compiler
CC=gc
# Indicate to the compiler to include header files in the local folder
CPPFLAGS = -I
main: method1.o
main: method2.o
main: method3.o
main: method4.o
main.o: main.h
Whereas method 1,2,3,4 is the functions of the main .c and I have the following problem when I type make in the shell:
make
gcc -I -c -o method1.o method1.c
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: ld returned 1 exit status
make: *** [method1.o] Error 1
Upvotes: 2
Views: 636
Reputation: 1465
CC=gcc
CPPFLAGS=-I include
VPATH=src include
main: main.o method1.o method2.o method3.o method4.o -lm
$(CC) $^ -o $@
main.o: main.c main.h
$(CC) $(CPPFLAGS) -c $<
method1.o: method1.c
$(CC) $(CPPFLAGS) -c $<
method2.o: method2.c
$(CC) $(CPPFLAGS) -c $<
method3.o: method3.c
$(CC) $(CPPFLAGS) -c $<
method4.o: method4.c
$(CC) $(CPPFLAGS) -c $<
it worked like this
Upvotes: 0
Reputation: 10158
The issue is in your CPPFLAGS
definition:
# Indicate to the compiler to include header files in the local folder
CPPFLAGS = -I
According to the comment above it, it misses a .
:
CPPFLAGS = -I.
Otherwise, gcc
will treat the -c
that comes after -I
in your command line as the name of a directory where it can search for headers. Thus, as far as gcc
is concerned there's no -c
option, and it will attempt to link method1.c
as a complete application, hence the error message complaining that there's no main
function.
Upvotes: 0
Reputation: 43578
if your project contains the following files: method1.c
method2.c
method3.c
method4.c
and main.c
you can use the following make file
CPPFLAGS=-I/path/to/header/files
CC=gcc
all: main
%.o: %.c
$(CC) $(CPPFLAGS) -c -o $@ $^
main: method1.o method2.o method3.o method4.o main.o
$(CC) -o $@ $^
Upvotes: 1