I can't understand what the problem is with this makefile?
I'm getting error No rule to make target `step.c', needed by `step.o'. Stop.
vertex: main.o step.o
gcc main.o step.o -o vertex
main.o: main.c header.h
gcc -c main.c
step.o: step.c header.h
gcc -c step.c
You don't have a file step.c so Make thinks you want it to generate one, but it doesn't know how.
Related
I'm trying to create a makefile titled 'p1' for a project.
When I try the command make p1 it returns with make: nothing to be done for p1
Also, when I try the command make p1 clean it returns no rule to make p1 'clean.' Stop
Here is my makefile:
a.out: main.o P1LinkedList.o const_iterator.o iterator.o Node.o
g++ -std=c++11 main.o const_iterator.o iterator.o Node.o
main.o:
g++ -std=c++11 -c main.cpp
P1LinkedList.o:
g++ -std=c++11 -c P1LinkedList.cpp
iterator.o:
g++ -std=c++11 -c iterator.cpp
const_iterator.o:
g++ -std=c++11 -c const_iterator.cpp
Node.o:
g++ -std=c++11 -c Node.cpp
depend:
g++ -MM main.cpp > p1.dep
clean:
rm -f a.out *.o
What do I need to fix to have the makefile compile .o files from my .cpp files and how do I fix the issue with the clean command?
Edit:
Here are the commands I've used to compile manually:
Helens-Air:p1a helenade$ g++ -std=c++11 *.cpp
Helens-Air:p1a helenade$ ./a.out
^^ and this just continues with the program execution from there
We may have to take this in stages.
First, you seem to misunderstand the difference between a makefile name and a target name. This appears to have been a miscommunication between you and your teacher, but it's easy to clear up.
Suppose you have a makefile named "Makefile", containing the following:
foo:
#echo running the foo rule
bar:
#echo running the bar rule
If you make foo, you will get:
running the foo rule
The argument (foo) tells Make which target to attempt to build. And how did Make know which makefile to use? (After all, you could have a dozen makefiles in the working directory.) You can specify which makefile to use, but if you don't then by default Make will look for a makefile named Makefile (or makefile or GNUmakefile, don't worry about this for now). To specify a makefile with another name, like "Buildfile", you can use the -f flag:
make -f Buildfile
So "p1" ought to have been the name of a target, not a makefile. Within the makefile, rename your a.out rule to p1. Then rename the whole makefile to Makefile. Then
make p1
should work (or at least run).
Edit:
I'll go out on a limb. In the a.out rule (which should now be called the p1 rule), I notice that you have left P1LinkedList.o out of the list of object files to be linked. So try changing it:
p1: main.o P1LinkedList.o const_iterator.o iterator.o Node.o
g++ -std=c++11 main.o P1LinkedList.o const_iterator.o iterator.o Node.o
If that works, you can simplify it with an automatic variable:
p1: main.o P1LinkedList.o const_iterator.o iterator.o Node.o
g++ -std=c++11 $^
And there will be other small improvements you can make.
If it doesn't work, try ls *.cpp and see if you've overlooked some other source file.
I'm trying to learn how to write makefiles. I have started reading the manual of gnu make: https://www.gnu.org/software/make/manual/html_node/Simple-Makefile.html#Simple-Makefile
I have 3 files in the same directory:
main.cpp: which creates a rectangle and prints some information. Therefor it includes Rectangle.h
Rectangle.h: header file for rectangle class
Rectangle.cpp: implementation of rectangle class
I am having troubles with the include of Rectangle.h in main.cpp. My makefile is:
main: main.o rectangle.o
g++ -o main.exe main.o rectangle.o
main.o: main.cpp
g++ main.cpp
rectangle.o: Rectangle.cpp
g++ Rectangle.cpp
clean:
rm main.exe main.o rectangle.o
I know something is missing to create main.o but I can't find out what it is. I tried adding various variations of Rectangle.h/.o/.cpp and finding something on the internet but I was unable to find something.
Help will be much appreciated :)
PS: The code is fine, I can compile it with the command:
g++ -o main.exe main.cpp Rectangle.cpp
man g++
When you invoke GCC, it normally does preprocessing, compilation, assembly and linking. The "overall options" allow you to stop this process at an intermediate stage. For example, the -c option says not to run the linker. Then the output consists of object files output by the assembler.
I recently tried to make a makefile and it works fine on my laptop. I was making a game in c++ and shared my code on github. One of my friends cloned
the repo and informed me that he ran into some errors. Coming to errors I must inform you that my project uses QuickCG which is based on SDL, so naturally one needs to have SDL installed. My friend did not have that initially but later downloaded it using sudo apt-get install libsdl1.2-dev. After downloading, the 'header include' error was removed but still there is linking error I suppose.
Here is my makefile
CC = g++
CFLAGS = -c -O3
CLINK_FLAGS = -lSDL
all : game
game : main.o quickcg.o
$(CC) main.o quickcg.o -o game $(CLINK_FLAGS)
main.o : main.cpp
$(CC) $(CFLAGS) main.cpp
quickcg.o : quickcg.cpp
$(CC) $(CFLAGS) quickcg.cpp
clean :
rm *.o game
My Game folder contains only 2 cpp files which are main.cpp and quickcg.cpp. It also contains 1 header file quickcg.h
Now to come to the exact error statement after executing make
g++ -c -O3 main.cpp
g++ -c -O3 quickcg.cpp
g++ main.o quickcg.o -o game -lSDL
/usr/bin/ld: cannot find -lSDL
collect2: error: ld returned 1 exit status
make: *** [game] Error 1
Please note that this worked completely fine on my laptop.
Also please note that the following command worked like a charm even on his laptop
g++ *.cpp -lSDL -O3
So clearly there seems to be a fault with makefile.
Forgive me if I have done anything stupid because I am new to makefiles but I am not able to find any errors here. Thanks in advance
You may try
CLINK_FLAGS = `sdl-config --libs`
if you don't know the path for -L.
I have main.cpp (including main function) and func1.cpp, and I want to link these files with a makefile. Classic form would be:
main: main.o func1.o
g++ main.o func1.o -o main
main.o: main.cpp
g++ -c main.cpp
func1.o: func1.cpp
g++ -c func1.cpp
or one can write
main: func1.o main.o
g++ main.o func1.o -o main
func1.o: func1.cpp
g++ -c func1.cpp
main.o: main.cpp
g++ -c main.cpp
or
main: main.o func1.o
g++ main.o func1.o -o main
func1.o: func1.cpp
g++ -c func1.cpp
main.o: main.cpp
g++ -c main.cpp
Do the last two differ from the classic one ? Does one have some advantages over the other?
No, the only time the order of the rules comes into play is when you just enter make, in which case it can choose the first rule as the default.
Beyond that, make is intelligent enough to execute dependent rules no matter where they are in the file.
There is no difference between the three sets of ruls. However, make knows how build .cpp files into object files, so all you really need is:
main: main.o func1.o
g++ main.o func1.o -o $#
I keep getting this error:
make: *** No rule to make target `all'. Stop.
Even though my make file looks like this:
CC=gcc
CFLAGS=-c -Wall
all: build
build: inputText.o outputText.o main.o
gcc main.o inputText.o outputText.o -o main
main.o: main.c
$(CC) $(CFLAGS) main.c -o main.o
inputText.o: inputText.c
$(CC) $(CFLAGS) inputText.c -o inputText.o
outputText.o: outputText.c
$(CC) $(CFLAGS) outputText.c -o outputText.o
Yes there should be a tab space underneath the target and there is in my make file.
I can get it to work if I try one of the targets like main.o, inputText.o and outputText.o but can't with either build or all.
EDIT:
I just randomly tried running make and telling it the file using the following command:
make -f make
This works but why doesn't just typing make work?
Your makefile should ideally be named makefile, not make. Note that you can call your makefile anything you like, but as you found, you then need the -f option with make to specify the name of the makefile. Using the default name of makefile just makes life easier.