I'm new to C programming, and I'm trying to compile this Simple training example with GCC on Ubuntu 12.10.
Looks like fann.h should not be included (as stated on the file itself), so I included fixedfann.h instead.
First attempt (without include, just to see what the compiler will ask for):
$ gcc main.c -o output
/tmp/cckKyM92.o: In function `main':
main.c:(.text+0x62): undefined reference to `fann_create_standard'
main.c:(.text+0x7a): undefined reference to `fann_set_activation_function_hidden'
main.c:(.text+0x8e): undefined reference to `fann_set_activation_function_output'
main.c:(.text+0xba): undefined reference to `fann_train_on_file'
main.c:(.text+0xce): undefined reference to `fann_save'
main.c:(.text+0xda): undefined reference to `fann_destroy'
collect2: ld returned 1 exit status
fann_create_standard is on fann.h and fann.c. As fann.h is included by fixedfann.h, and fann.h should not be included directly, I believe I have to compile fann.c and fixedfann.c, and link then (tell me if I'm doing any mistake, I'm still not familiar with this "linking" stuff).
So I did:
$ gcc fann/fixedfann.c -o fann/fixedfann.o
fann/fixedfann.c:22:20: fatal error: config.h: No such file or directory
compilation terminated.
and then I did:
$ gcc fann/fixedfann.c -o fann/fixedfann.o -include fann/include/config.h
fann/fixedfann.c:22:20: fatal error: config.h: No such file or directory
compilation terminated.
Now, why it's not finding the config.h file here?
--update
Thanks #JonathanLeffler, I could make some steps here. But now I'm stuck at:
$ gcc fann/fixedfann.c -o fann/fixedfann.o -I./fann/include/ -lm
/usr/lib/gcc/i686-linux-gnu/4.6/../../../i386-linux-gnu/crt1.o: In function `_start':
(.text+0x18): undefined reference to `main'
collect2: ld returned 1 exit status
and, with grep, I could not find any reference to main on the fann folder... Also no function _start, and I don't know who is linking this crt1.o... Any idea what's wrong here?
--update2
Ok, I got the .o files using Harmeet's Makefile, now I'm trying to link everything.
I created the main.o with gcc -c main.c, and I tried:
gcc -o output main.o fann/fixedfann.o -lm
(-lm for the libmath, that is needed) and I got:
main.c:(.text+0xba): undefined reference to `fann_train_on_file'
This fann_train_on_file is on fann_train_data.c, so I tried:
gcc -o output main.o fann/fixedfann.o fann/fann_train_data.o -lm
but I got lots of multiple definition of... errors... :/
Looks like fann_train_data.o is already included/linked, but if so, why it's not finding fann_train_on_file?
--update3
I'm still really stuck here... Any idea of which (if any) of this two lines should work?:
gcc -o output main.o hello.o fann/fixedfann.o fann/fann_train_data.o -lm
or
gcc -o output main.o hello.o fann/fixedfann.o -lm
--update for Harmeet
The output was:
$ make
gcc -L./fann -lfann main.o -o main
main.o: In function `main':
main.c:(.text+0x62): undefined reference to `fann_create_standard'
main.c:(.text+0x7a): undefined reference to `fann_set_activation_function_hidden'
main.c:(.text+0x8e): undefined reference to `fann_set_activation_function_output'
main.c:(.text+0xba): undefined reference to `fann_train_on_file'
main.c:(.text+0xce): undefined reference to `fann_save'
main.c:(.text+0xda): undefined reference to `fann_destroy'
collect2: ld returned 1 exit status
make: *** [main] Error 1
You can use ar to make a static library and work with that.
Create a Makefile under your hello-fann-3/fann/ folder with the following contents -
SOURCES = $(wildcard *.c)
OBJECTS = $(SOURCES:.c=.o)
CFLAGS = -c -Iinclude
all: libfann.a
libfann.a: $(OBJECTS)
ar rcs $# $^
%.o: %.c
gcc $(CFLAGS) $^
Then use the make command in hello-fann-3/fann/ to build the static library. The above Makefile will generate libfann.a that you can link to your program.
Create a Makefile under your hello-fann-3/ folder with the following contents -
SOURCES = $(wildcard *.c)
OBJECTS = $(SOURCES:.c=.o)
CFLAGS = -c -I./fann/include
LFLAGS = -L./fann -lfann
main: $(OBJECTS)
gcc $(LFLAGS) $^ -o $#
%.o: %.c
gcc $(CFLAGS) $^
Then use the make command in hello-fann-3/ to build the main program.
In your main.c, you must include fan.h like -
#include "fann.h"
If you do not understand the Makefile, you can read about it here -
http://www.gnu.org/software/make/manual/html_node/index.html
You just need to link the fann library.
If you compile manually do this
gcc main.c -lfann -lm -o main
then simply run it like
./main
If you are on Ubuntu and you faced the following error
./main: error while loading shared libraries: libfann.so.2: cannot open shared object file: No such file or directory
Then run
sudo ldconfig
If you are using NetBeans, then simply Right click on your project -> Properties -> Build -> Linker,
then in the Libraries section click on the browse button [...] then in the new window click on Add Library...
Then add fann library (for example my fann library path is: /usr/local/lib/libfann.a) and click Ok
A fellow helped me, and we came to this line that compiled everything, and make the executable:
$ gcc fann/fann.c fann/fann_io.c fann/fann_train.c fann/fann_train_data.c fann/fann_error.c fann/fann_cascade.c main.c -Ifann/include -lm
And this is the answer.
That said, this is exactly what fixedfann.c is doing (include all this .c files). But if I try:
$ gcc fann/fixedfann.c main.c -Ifann/include -lm
..I get:
undefined reference to `fann_train_on_file'
This fann_train_on_file is on fann_train_data.c, which is included by fixedfann.c, so why it is undefined? I don't know... :/
--update
I realized that:
$ gcc fann/fixedfann.c main.c -Ifann/include -lm
will work if I comment the headers on fixedfann.c:
//#include "config.h"
//#include "fixedfann.h"
#include "fann.c"
#include "fann_io.c"
#include "fann_train.c"
#include "fann_train_data.c"
#include "fann_error.c"
#include "fann_cascade.c"
Related
I am working on a simple project that generates 2 executable files, main and Server.
The program in Main.c makes use of code present in user_interface.c through the header file user_interface.h.
The Makefile I have written is as follows,
all: main user_interface.o Server
main: user_interface.o main.c
gcc main.c user_interface.o -o main
user_interface.o: user_interface.c user_interface.h
gcc user_interface.c -o user_interface.o
Server: Server.c
gcc Server.c -o Server
clean:
rm -rf main *.o Server
When I type make on the terminal, I get the following error:
gcc user_interface.c -o user_interface.o
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status
make: *** [Makefile:18: user_interface.o] Error 1
How do I navigate past this error?
Your rule for user_interface.o is wrong. You need to use the -c option to tell it that it's creating an object file rather than an executable, so it doesn't need a main() function.
all: main Server
main: user_interface.o main.o
gcc main.o user_interface.o -o main
main.o: main.c
gcc -c main.c
user_interface.o: user_interface.c
gcc -c user_interface.o
Server: Server.c
gcc Server.c -o Server
clean:
rm -rf main *.o Server
make actually has a built-in rule for compiling .c to .o, so you don't actually need those rules.
I think you're not using makefiles properly.
so a section of your makefile might look something like this:
core: WitchCraft NeuralServer AmoebaServer CDS NLPServer HollyServer
test: ENiX4NeuralCLI DataInjector NNTestServer ENiX4AmoebaCLI CLINLPTest
WitchCraft: ENiX_Net.o ENiX_IPC.o ENiX_SHM.o ENiX_Seq.o ENiX_Packet.o WitchCraft.o ENiX_Config.o ENiX_Disk.o ENiX_Binary.o
g++ -ggdb -O0 ENiX_Net.o ENiX_IPC.o ENiX_SHM.o ENiX_Seq.o ENiX_Packet.o WitchCraft.o ENiX_Config.o ENiX_Disk.o ENiX_Binary.o -o WitchCraft.bin -std=c++11 -lreadline
These things before the colon, are called targets. The can be called with:
make <target>
e.g.
make WitchCraft
So for the first line of your target you've got source files inside there for some reason and it looks like you're trying to compile user_interface.o as a binary, rather than an object, but you're not linking it to main.o.
So I suspect you want something like:
main: main.o user_interface.o
gcc main.o user_interface.o -o main
And what that should do is cause make to look for the source code for main.o (i.e. main.c) likewise for interface.o (i.e. interface.c) and then compile these into object files (i.e. .o files).
Then you'd link these object files into a binary, using gcc with the -o to specify the binary output file in this case, "main".
And you'd need to do something similar with the server.
ok, so i'm trying to compile my code using makefile, i've got only 2 .c file and 1 .h file, i used "sqrt()" function from math.h (only in main), here is my makefile:
a.out: GBST.o main.o
gcc GBST.o main.o
GBST.o: GBST.c GBST.h
gcc -c GBST.c
main.o: main.c
gcc -c main.c -lm
still, I get main.c:(.text+0x170): undefined reference to `sqrt' error, what can it be? (btw, i wrote -lm in GBST line before and it did not help, so i have deleted it)
You need to use -lm in the link line, not in the compile line.
a.out: GBST.o main.o
gcc GBST.o main.o -lm
# ^^^^ Need it here
GBST.o: GBST.c GBST.h
gcc -c GBST.c
main.o: main.c
gcc -c main.c
# ^^^^ Don't need it here
I'm trying to install PintOS on my local Ubuntu 14.04 machine. When I try to run make to compile the utilities. I get the following error.
ankitkal#ankitkal-Inspiron-5521:~/os/pintos/src/utils$ ls
backtrace Makefile pintos pintos.~1.55.~ pintos-mkdisk setitimer-helper.o squish-unix.c
CVS Makefile~ pintos~ pintos-gdb setitimer-helper.c squish-pty.c
ankitkal#ankitkal-Inspiron-5521:~/os/pintos/src/utils$ make
gcc -lm setitimer-helper.o -o setitimer-helper
setitimer-helper.o: In function `main':
setitimer-helper.c:(.text+0xbe): undefined reference to `floor'
collect2: error: ld returned 1 exit status
make: *** [setitimer-helper] Error 1
ankitkal#ankitkal-Inspiron-5521:~/os/pintos/src/utils$
The maths library (for the <math.h> header which is used in setitimer-helper.c) is not getting linked properly. When I look into the Makefile, this is the output.
ankitkal#ankitkal-Inspiron-5521:~/os/pintos/src/utils$ cat Makefile
all: setitimer-helper squish-pty squish-unix
CC = gcc
CFLAGS = -Wall -W
LDFLAGS = -lm
setitimer-helper: setitimer-helper.o
squish-pty: squish-pty.o
squish-unix: squish-unix.o
clean:
rm -f *.o setitimer-helper squish-pty squish-unix
Please tell me how to fix it. I'm using gcc-4.8.6 by the way.
gcc -lm setitimer-helper.o -o setitimer-helper
The problem is in the order of your arguments to GCC. Try this:
gcc -o setitimer-helper setitimer-helper.o -lm
This is because of the way that ld resolves undefined symbols when linking. Basically, the way you had it before, ld first sees -lm and says "I have no reason to include this library". It then includes your setitimer-helper.o which has an unresolved reference to floor. After that, there are no more libraries to consider, and floor remains unresolved.
If -lm comes afterward, it is able to resolve the reference to floor.
I'm trying to compile a few .c files that used msgpack-c functions into a shared library. I have the following Makefile:
MSGPACK_CS = msgpack.c
CFLAGS = -std=c99
MSGPACK_OBJECTS = $(subst .c,.o,$(MSGPACK_CS))
MSGPACK_LIBS = msgpack.so
all: $(MSGPACK_OBJECTS) $(MSGPACK_LIBS)
%.o: %.c
$(CC) -c -shared -fPIC $(CFLAGS) $<
$(MSGPACK_LIBS): $(MSGPACK_OBJECTS)
ld -Lmsgpack/.libs -share -o $# $(MSGPACK_OBJECTS) -lmsgpack
I can compile a program that uses msgpack without problem, but this gives me the following error:
msgpack.o: In function `msgpack_pack_int64':
/usr/local/include/msgpack/pack_template.h:373: undefined reference to `__stack_chk_fail_local'
ld: msgpack.so: hidden symbol `__stack_chk_fail_local' isn't defined
ld: final link failed: Bad value
Apparently the linkage process isn't going well, but I don't know what is wrong. What can I do?
Try linking with the gcc driver instead of calling ld directly. ld doesn't know about the gcc support libs that are needed for the C runtime:
gcc -Lmsgpack/.libs -shared -o $# $(MSGPACK_OBJECTS) -lmsgpack
If this still doesnt't work, you might need to add -fno-stack-protector to your CFLAGS to supress runtime stack checking.
I had some issues earlier with declaring my array set of records. Now I think there is something wrong with my Makefile or something.
Here is my Makefile:
EEXEC = proj1
CC = gcc
CFLAGS = -c -Wall
$(EXEC) : main.o set.o
$(CC) -o $(EXEC) main.o set.o
main.o : main.h main.c
$(CC) $(CFLAGS) main.c
set.o : set.h set.c
$(CC) $(CFLAGS) set.c
There are more functions I have in my set.c file but these are the functions I am testing at the moment:
DisjointSet *CreateSet(int numElements);
DisjointSet *MakeSet(DisjointSet *S,int ele, int r);
void Print(DisjointSet *S);
And the errors I am receiving in the terminal is:
main.o: In function `main':
main.c:(.text+0x19): undefined reference to `CreateSet'
main.c:(.text+0x43): undefined reference to `MakeSet'
main.c:(.text+0x5f): undefined reference to `Print'
The errors that you're getting are linker errors, telling you that while linking your program the linker can't find a function named 'CreateSet' (etc.). It's not immediately obvious why that should be the case, because it appears that you're including "set.o" in the build command.
To troubleshoot build problems, it's often useful to figure out what make is trying to do, and then run the commands individually one at a time so you can see where things go wrong. "make -n" will show you what commands "make" would run, without actually doing them. I would expect to see a command like:
gcc -o proj1 main.o set.o
try running that by hand and see where it gets you.
Make sure you have included set.h in main.c
Also you declare EEXEC but use EXEC...
If these are all on one line in the makefile:
EEXEC = proj1 CC = gcc CFLAGS = -c -Wall
Then you have one macro EEXEC whose value is proj1 CC = gcc CFLAGS = -c -Wall, and you have no CC or CFLAGS macro. CC probably has a default, which is why that much is working.