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Errors that refer to a bunch of unresolved OpenSSL symbols that clearly exist?
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Closed 6 years ago.
I'm attempting to use OpenSSL's EVP interface to do some encryption. I'm pretty sure my code is right, but I can't seem to get it to compile. I'm using GCC, and Ubuntu 32-bit precise with libssl-dev installed and at the latest version.
The project currently consists of one file, program.c.
#include <openssl/evp.h>
...
i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha1() ... );
...
EVP_CIPHER_CTX_init(e_ctx);
among other various calls.
Here is how I invoke gcc:
gcc -Wall -g -lssl -lcrypto -o program program.c
Then I get output like this
/home/andy/program/program.c:31: undefined reference to `EVP_sha1'
/home/andy/program/program.c:31: undefined reference to `EVP_aes_256_cbc'
/home/andy/program/program.c:31: undefined reference to `EVP_BytesToKey'
/home/andy/program/program.c:44: undefined reference to `EVP_CIPHER_CTX_init'
So the include is clearly working:
andy#ProgStation2:/usr/include$ find . | grep evp.h
./openssl/evp.h
Here is the output of locate libcrypto. My best guess is that this is a stupid location for it and is why my link is failing, so I tried -L/usr/lib/i386-linux-gnu before -lcrypto with no luck as well.
/lib/i386-linux-gnu/libcrypto.so.1.0.0
I'm kind of stumped. If anyone wants to make me feel like a fool, I'd be very excited to figure out what i'm doing wrong!
It turns out it was something stupid. In the linker step, I was using gcc -Wall -g -lssl -lcrypto -o program program.o. I needed to move the library links to after the object file I was linking, and put libssl before libcrypto:
gcc -Wall -g -o program program.o -lssl -lcrypto
Try including headers using -I option, Look into directory for library using -L and finally specifying the library name with -l
Just making guess here, please specify path based on actual location.
gcc -g -Wall -L/usr/lib -I/usr/include -lssl -lcrypto -o program program.c
Hope it may help.
Related
Problem with linking portaudio into an c program on Linux.
System: Linux Ubuntu 20.4 i5 16 GB
ALSA and pulseaudio were preinstralled.
gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
gcc -Wall wm_1.c -lm libportaudio.a -o wm_1
The linker gives me more than 100 error messages all of type "undefined reference"
Here 2 examples out of >100
/home/max/Desktop/dev/portaudio/src/hostapi/alsa/pa_linux_alsa.c:504: undefined reference to snd_pcm_status_get_delay' /home/max/Desktop/dev/portaudio/src/hostapi/oss/pa_unix_oss.c:1778: undefined reference to __pthread_unregister_cancel'
So its obvious that the named parameter/function can not be found.
The error messages all point to source files in the source directory (the directory of the portaudio
package I downloaded to creatie the libs which were all created without error.
The libs are in /usr/local/..
libportaudio.a libportaudio.la libportaudio.so libportaudio.so.2 libportaudio.so.2.0.0 pkgconfig python3.8
and I copied libportaudio.a into the project directory. The lib has a a size of 1.1 MB .
if I use the dynamic libportaudio.so I get the error messages at run time.
I suspect that something went totally wrong with creating the libraries but I have no idea how to solve that
Other option:
Linking parameter or files missing ?
Header file ?
The same program compiles, links and runs without any problem on a iMac OS 10.13.6
where I used the dynamic lib .dylib.
gcc -v wm_1.c libportaudio.dylib -o wm_1
From the documentation:
Note that you will usually need to link with the approriate libraries that you used, such as ALSA and JACK, as well as with librt and libpthread. For example:
gcc main.c libportaudio.a -lrt -lm -lasound -ljack -pthread -o YOUR_BINARY
A little googling goes a long way...
This works:
gcc -Wall wm_1.c -lm libportaudio.a -lasound -pthread -o test.
gcc main.c libportaudio.a -lrt -lm -lasound -ljack -pthread -o YOUR_BINARY
I used that page and the command line at the begin using all 3 parameter but got errors, probably of misspelling, so I gave up on that (also because on the Mac OS it was not necessary). It now links without errors using -lasound and -pthread only (-pthread alone gives still errors and the use/not use of -ljack makes no difference).
I get some errors when I run the program but probably because of missing or wrong ALSA parameter settings. I found -pthread but I could not find -ljack and -lasound.
So the question: what are this 2 parameter doing?
It must be link parameter, but where is the documentation, I searched ld and gcc and did not find anything, while -pthread is documented.
probably this is a trivial newbie question, however, I can't figure out how to solve it.
I'm trying to build a test program using libtiff (test program copied from here). I've downloaded the static library libtiff.lib as well as the required header file tiffio.h. When I compile the main c function with no problem I have a main.o file. When I try to link main.o with libtiff using this command
gcc -g -Wall -o test.exe ./libtiff.lib ./test.o
I have this error:
undefined reference to `_imp__TIFFOpen'
I've looked into the lib file with nm -A libtiff.lib command and I can find this line
libtiff.lib:libtiff3.dll:00000000 I __imp__TIFFOpen
but it has 2 leading underscores instead of 1 as required by the linker. I'm using mingw on Windows 7 and all the required files are in the same directory.
No clue how to link with no errors.
Thanks in advance.
As suggested in the the comments, it was sufficient to invert the order of objects passed as arguments:
gcc -g -Wall -o test.exe ./test.o ./libtiff.lib
I'm trying to compile and link some .c file. I have been using Eclipse IDE for C/C++ developers, and in my local machine i can compile without problems. However, when i try to compile and link the same file in a RedHat OS (gcc version is 4.9.2-6 in this OS) i'm having problems. I get some warnings at compile time, but those are fine, i think, i just ignored and the application still runs fine. Here are the commands i executed and the associated output:
gcc -O0 -g3 -Wall -c -fmessage-length=0 -std=c99 -MMD -MP -MF"example.d" -MT"example.d" -o "example.o" "example.c"
warning: suggest parentheses around assignment used as truth value [-Wparentheses]
warning: implicit declaration of function ‘wait’ [-Wimplicit-function-declaration]
This generates two files, example.d and example.o. Then, i try to link them, without luck, with the following command:
gcc -Xlinker -L/usr/lib -lrt -static -pthread example.o -o example
/usr/bin/ld: cannot find -lrt
/usr/bin/ld: cannot find -lpthread
/usr/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status
The commands are taken directly from the ones that Eclipse generates, and work just fine in my local computer (Ubuntu OS) but not in the RedHat environment. The last command didn't work, with and without the -L option. I suppose the directory in -L is fine, as i run, for example,
locate libpthread.so
And one of the locations i get is /usr/lib (also /usr/lib64, but neither work).
Any help will be greatly appreciated!! :)
If you try to link a static executable, it will look for the *.a versions of the libraries, not what you usually want. Remove the -static flag. Or you can install the static libraries if you really want to. It also should not be necessary to add -L/usr/lib explicitly.
I'm trying to compile some c code via make with gcc, but I keep getting:
/usr/bin/ld: cannot find -lnetlink
I have -lnetlink included in the gcc make parameters. Using locate netlink is able to find multiple items. I've even told gcc exactly where to find one by using -L/usr/include/linux, but it still gives the error.
The gcc command arguments below:
gcc -g -ggdb -Wall -Wextra -o mt6d mt6d.o address_worker.o tunnel_worker.o mt6d_assoc.o addr_gen.o send_utils.o if_utils.o tun_utils.o icmp_utils.o utils.o -lcrypto -lssl -lnetlink -lpthread -lnetfilter_queue
I've also been having errors with libnetlink.h, but was able to get them resolved, but I've included that here if that might be related and this error appears immediately after the other was fixed. Fixed by using C_INCLUDE_PATH
I've recently upgraded to Ubuntu 13.04 and was using 11.04 before that.
Let me know if you need any more information. Any help would be greatly appreciated!
Thanks,
-Alan
I'm trying to compile some c code via make with gcc, but I keep getting:
Technically, this stage is called linking. That difference may seem subtle at first, but it's a really important one and can help frame the investigation when problems like this arise.
You should not reference /usr/include paths with -L. -L adds to the search path for libraries and generally only header files should show up under /usr/include.
libnl enables pkg-config, so you should use that.
For example (assuming you have libnl-3-dev installed):
gcc -o my_executable $(pkg-config --libs libnl-3.0) my_foo.o my_bar.o
In a Makefile, you could do the following to achieve that effect:
LDLIBS+=$(shell pkg-config --libs libnl-3.0)
CFLAGS+=$(shell pkg-config --cflags libnl-3.0)
I am trying to create an C application on Debian GNU/Linux which uses the PortAudio interface. To do this I must compile my program with gcc -lrt -lasound -ljack -lpthread -o YOUR_BINARY main.c libportaudio.a from this docs.
For this I installed libasound2-dev, and I checked where the files are using apt-file search libasound.so, this is the output:
lib32asound2: /usr/lib32/libasound.so.2
lib32asound2: /usr/lib32/libasound.so.2.0.0
lib32asound2-dev: /usr/lib32/libasound.so
libasound2: /usr/lib/x86_64-linux-gnu/libasound.so.2
libasound2: /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0
libasound2-dev: /usr/lib/x86_64-linux-gnu/libasound.so
So the libasound should be installed correctly, but when I compile my program with this makefile:
DMXTest: main.c libdmx.a
gcc -static -Wall main.c -L. -ldmx -lusb -lrt -lasound -ljack -lfftw3 -g -o main libportaudio.a
I get the following error: /usr/bin/ld: cannot find -lasound.
How can I link this library correctly?
You don't have libasound.a for -static, you will need that, or you can almost certainly just remove -static from the Makefile (likely in LDFLAGS or CFLAGS).
There's is a related Debian bug 522544, and a related Ubuntu bug #993959.
You may be able to build your own libasound from source, though as it also uses other libraries (notably libpthread.so, librt.so and libdl.so) I suspect it may remove some functionality when you build it statically, though it's supported with ./configure --enable-static at build time
(or try --enable-shared=no --enable-static=yes).
FWIW, the use of static binaries is "discouraged" by the glibc maintainers, though I don't agree...
To compile my code i used the following command
gcc -o rec_mic rec_mic.c -lasound
and it works perfectly, without create my own static library.