I tried to run .c file called grover.c in this C application libquantum
www.libquantum.de/files/libquantum-1.1.1.tar.gz
Now I this application already contains a Makefile.in and I can generate the executables called shor and grover using the command
./configure
make
make demos
But when I try to run grover.c using gcc or clan like this
clang grover.c
It gives me error of lots of undefined function reference.
In function oracle':
grover.c:(.text+0x50): undefined reference toquantum_sigma_x'
grover.c:(.text+0x89): undefined reference to quantum_toffoli'
grover.c:(.text+0xc8): undefined reference toquantum_toffoli'
grover.c:(.text+0xf2): undefined reference to quantum_cnot'
grover.c:(.text+0x137): undefined reference toquantum_toffoli'
grover.c:(.text+0x16b): undefined reference to quantum_toffoli'
grover.c:(.text+0x1b0): undefined reference toquantum_sigma_x'
I need to know how can I remove this error and if I can run this c code called grover.c in this application.
Thanks,
It looks like your compiler can not find one or more libraries to link to. My hunch is that the makefile has the appropriate commands to invoke the linker.
If you look at your makefile, you probably will see some commands like -L -l,
when the flag -L add a directory to the default search path for libraries and the flag -l is used to name the library to link.
for example -L/lib/openGL -lglut32 would cause the library libglut32.so.X.Y.Z which is found in the directory /lib/openGL. (not this is for a Linux system, but it should be fairly similar for Mac).
N.B. X.Y.Z are the version number of the library.
Once you work this out, there may be issues with the load finding the libraries, especially if they are in non-standard locations.
------------------------ edit --------------------------
After I posted this, and went to bed I realized that I missed a potential case (and thanks to Paul Griffiths for also noticing my omission.....teach me to do multiple things at once).
Any how, just compiling a simple file, say hello.c, as clang hello.c -o hello works because everything is in one file and clang will automatically link to the C run-time library.
If, in your case the code is spread across multiple files, say grover.c and file1.c you would need to do:
clang -c grover.c -o grover.o
clang -c file1.c -o file1.o
clang grover.o file1.o -o grover
(or alteratively clang grover.c file1.c -o grover)
SO what the first two lines are doing is translating the source-code files (grover.c and file1.c) into object files. THe third line covers the two object files into an executable.
Finally, both these cases can be involved. You could have multiple files as well as missing libraries.
Related
Good Day Everyone,
N.B - This problem has been solved - I have provided my own solution in the answer section however the solution provided by Jonathan is much shorter. Nevertheless, this was the following question I originally posted:
I am basically trying to compile a serial library (for UART communication) on Linux however I am not really sure how to correctly compile (I have mentioned what I have done so far below), any suggestions would be highly valuable. I am using the serialib library - which is composed of 2 main files (serialib.h and serialib.cpp) , you may directly view the source code of these files here (scroll all the way to the bottom and view the files in new tabs): http://serialib.free.fr/html/classserialib.html
I transferred these files (serialib.h and serialib.cpp) to my BeagleBone Black micro-controller which is running Debian (Wheezy) , g++/gcc (Debian 4.6.3-14) 4.6.3. I wrote my own program (uart.cpp is my file name) to access the functions provided by this library, this is what I wrote:
#include <iostream>
#include "serialib.h"
#ifdef __linux__
#define DEVICE_PORT "/dev/ttyO1"
#endif
int main()
{
serialib LS;
return 0;
}
So as you can see I am trying to access the 'seriallib' class. serialib.h, serialib.cpp and uart.cpp are all in the home directory. I also manually added the iostream library in serialib.cpp as I did not see it being declared in the original source code.
Now I am really unsure of how to compile such external libraries but so far I tried the following steps:
g++ -c -Wall -Werror -fPIC serialib.c to convert to PIC which gives the following error:
distcc[3142] (dcc_parse_hosts) Warning: /home/debian/.distcc/zeroconf/hosts contained no hosts; can't distribute work
distcc[3142] (dcc_zeroconf_add_hosts) CRITICAL! failed to parse host file.
distcc[3142] (dcc_build_somewhere) Warning: failed to distribute, running locally instead
g++ serialib.cpp -L /home/debian/serialib.h which gives the following error:
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../arm-linux-gnueabihf/crt1.o: In function _start':
(.text+0x30): undefined reference tomain'
collect2: ld returned 1 exit status
distcc[3210] ERROR: compile serialib.cpp on localhost failed
As of now I am still finding out how to compile this and if I manage to work this out then I'll post my solution here too. Once again any suggestion will be highly valuable. Thank you all :) .
g++ -c -Wall -Werror -fPIC serialib.c to convert to PIC which gives the following error:
The "error" is not an error, it's a warning, telling you that your distcc setup is broken, but that it compiled locally.
That command doesn't "convert to PIC", it compiles the file serialib.c and produces a compiled object file, serialib.o
g++ serialib.cpp -L /home/debian/serialib.h
This is just nonsense. It tries to build a program from serialib.cpp and use the directory /home/debian/serialib.h (which isn't a directory!) to find libraries.
You don't need to "compile a library" you can just compile both the source files and link them together into a program. Either:
g++ -c serialib.cpp
g++ -c uart.cpp
g++ serialib.o uart.o -o uart
Or all in one command:
g++ serialib.cpp uart.cpp -o uart
You should read An Introduction to GCC to understand the commands, not just enter bogus commands without understanding them.
I have found a solution to this problem, hope this helps for all the future readers with similar problems. I have my own source code uart.cpp (Given in the question) which I want to compile, the external library is serialib that contains two main files (serialib.h and serialib.cpp), you will want to replace the following commands with respect to the files you have
Step 1: Compiling with position independent code
g++ -c -Wall -Werror -fpic serialib.cpp
Step 2: Creating a shared library
g++ -shared -o libserialib.so serialib.o , here the library is libserialib.so.
Step 3: Linking your source code with library
g++ -L /home/debian -lserialib uart.cpp -o uart
g++ -L /home/debian -Wall -o test uart.cpp -lserialib
You may save the library at a different path and you may have a different name of course. Suppose you have a library called libabc.so at the directory /home/user/myDir then the commands will be like:
g++ -L /home/user/myDir -labc your_code.cpp -o your_code
g++ -L /home/user/myDir -Wall -o test your_code.cpp -labc
test is out own program, lserialib is actually looking for libserialib.so and not serialib.o as gcc/g++ assumes all libraries start with lib and end with .so or .a and you can see the same goes for labc as it will look for libabc.so thus it is important to make sure your library name begins with lib and ends with .so or .a
Step 4: Making library available at run time
Here we provide the path where the library is actually stored, I saved it in the directory /home/debian which is why my command looks like:
export LD_LIBRARY_PATH=/home/debian:$LD_LIBRARY_PATH
if your library is saved at /path/to/file then the command will look like:
export LD_LIBRARY_PATH=/path/to/file:$LD_LIBRARY_PATH
This is to help the loader find the shared library and to view this path: echo $LD_LIBRARY_PATH and to unset this: unset LD_LIBRARY_PATH
To execute the program type either ./test or ./uart and in case of any modification to the main source code (uart.cpp in this case) , simply repeat step 3. I found the following link very useful: http://www.cprogramming.com/tutorial/shared-libraries-linux-gcc.html . Thank you to all of you who took time to read this question and especially those who gave me suggestions. If anyone has more or better solutions, feel free to post them here to assist future readers :).
I compiled the object files, and then tried to compile the executable, which failed by saying that there are undefined references to functions in "theLib".
g++ -I./theLib/src -c -o obj/main.o src/main.cpp
(works so far)
g++ -L./theLib -Wl,-rpath=./theLib obj/main.o -ltheLib -o exe
(error: libtheLib.so: undefined reference to 'some_function')
I checked for answers everywhere, and they all just suggest moving the -ltheLib part after the dependencies (which I did). But it still doesn't work. What really boggles my mind is that the same library compiles just fine for an example in a different directory.
The library is in C. Can that mess up trying to compile C++? Or am I just missing something with compiling the .o files first?
Turns out the library depended on functions that I had to implement and provide in my own source code. I never knew that some libraries did that, but lesson learned. Once I implemented the functions that were causing the errors and added those source files, it worked.
I'm currently learning OpenCL. Now, when I want to compile my program, I get an error with this command:
g++ -Wall -l OpenCL main.cpp -o main
The errors are mostly undefined references, because the library is not linked, I think (nevertheless I will post the error code at the end).
But with this command everything works fine:
g++ -Wall main.cpp -o main -l OpenCL
So my question is, what do I have to do, to use the -l Flag in front of the command?
(The Background is: I want to use Netbeans to compile my programm and when i add the flag under -> properties -> build -> C++ Compiler -> additional options, it will put in in the Position, shown in the first command)
Thanks in advance for your help
Here's the error code:
/tmp/ccmKP4oI.o: In function `cl::detail::ReferenceHandler<_cl_context*>::release(_cl_context*)':
main.cpp:(.text._ZN2cl6detail16ReferenceHandlerIP11_cl_contextE7releaseES3_[_ZN2cl6detail16ReferenceHandlerIP11_cl_contextE7releaseES3_]+0x14): undefined reference to `clReleaseContext'
/tmp/ccmKP4oI.o: In function `cl::detail::ReferenceHandler<_cl_command_queue*>::release(_cl_command_queue*)':
main.cpp:(.text._ZN2cl6detail16ReferenceHandlerIP17_cl_command_queueE7releaseES3_[_ZN2cl6detail16ReferenceHandlerIP17_cl_command_queueE7releaseES3_]+0x14): undefined reference to `clReleaseCommandQueue'
/tmp/ccmKP4oI.o: In function `cl::Platform::getInfo(unsigned int, std::string*) const':
main.cpp:(.text._ZNK2cl8Platform7getInfoEjPSs[_ZNK2cl8Platform7getInfoEjPSs]+0x22): undefined reference to `clGetPlatformInfo'
/tmp/ccmKP4oI.o: In function `cl::Platform::get(std::vector<cl::Platform, std::allocator<cl::Platform> >*)':
main.cpp:(.text._ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE[_ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE]+0x41): undefined reference to `clGetPlatformIDs'
main.cpp:(.text._ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE[_ZN2cl8Platform3getEPSt6vectorIS0_SaIS0_EE]+0xb4): undefined reference to `clGetPlatformIDs'
collect2: error: ld returned 1 exit status
Order of [most] arguments to g++ is very important.
Libraries should go last (at least after source and object files). You can't really change that.
The -l should preferably be glued to the library name:
g++ -Wall main.cpp -o main -lOpenCL
# ^^^ glue the -l to the library name
You probably want to also pass -g (in addition of -Wall) to the compiler to get a debuggable binary. Use the gdb debugger.
As James Kanze commented, you might want to replace -g with -ggdb if using specifically gdb.
With g++ (and generally under Unix), -l specifies a source of
input (either a .a or a .so), and input is processed in
order. When the input is a static library (a .a file), it
will be scanned for objects which resolve undefined references;
if it is a .so, there aren't any object files in it, but it
will still only be taken into consideration if it resolves some
undefined symbol.
When you put the -l before any object files, there are no
undefined symbols yet, so nothing will be incorporated into the
program.
I have two simple files:
runner.cpp:
#define BOOST_TEST_DYN_LINK
#define BOOST_TEST_MODULE Main
#include <boost/test/unit_test.hpp>
and test1.cpp:
#define BOOST_TEST_DYN_LINK
#ifdef STAND_ALONE
# define BOOST_TEST_MODULE Main
#endif
#include <boost/test/unit_test.hpp>
BOOST_AUTO_TEST_SUITE( Foo)
BOOST_AUTO_TEST_CASE( TestSomething )
{
BOOST_CHECK( true );
}
BOOST_AUTO_TEST_SUITE_END()
To compile, I'm using:
$ g++ -I/e/code/boost_1_52_0 -o runner -lboost_unit_test_framework runner.cpp test1.cpp
I get the following error:
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ccU0cDSz.o:runner.cpp:(.text+0x8c): multiple definition of `main'
c:/pdev/mingw/bin/../lib/gcc/i686-pc-mingw32/4.7.2/../../../libboost_unit_test_framework.a(unit_test_main.o):unit_test_main.cpp:(.text.startup+0x0): first defined here
c:/pdev/mingw/bin/../lib/gcc/i686-pc-mingw32/4.7.2/../../../libboost_unit_test_framework.a(unit_test_main.o):unit_test_main.cpp:(.text.startup+0x14): undefined reference to `init_unit_test_suite(int, char**)'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ccU0cDSz.o:runner.cpp:(.text+0x52): undefined reference to `_imp___ZN5boost9unit_test9framework17master_test_suiteEv'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ccU0cDSz.o:runner.cpp:(.text+0xb0): undefined reference to `_imp___ZN5boost9unit_test14unit_test_mainEPFbvEiPPc'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ccU0cDSz.o:runner.cpp:(.text$_ZN5boost9unit_test13test_observerD2Ev[__ZN5boost9unit_test13test_observerD2Ev]+0xe): undefined reference to `_imp___ZTVN5boost9unit_test13test_observerE'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ccU0cDSz.o:runner.cpp:(.text$_ZN5boost9unit_test13test_observerC2Ev[__ZN5boost9unit_test13test_observerC2Ev]+0xe): undefined reference to `_imp___ZTVN5boost9unit_test13test_observerE'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ccU0cDSz.o:runner.cpp:(.text$_ZN5boost9unit_test15unit_test_log_tC1Ev[__ZN5boost9unit_test15unit_test_log_tC1Ev]+0x22): undefined reference to `_imp___ZTVN5boost9unit_test15unit_test_log_tE'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text+0x88): undefined reference to `_imp___ZN5boost9unit_test15unit_test_log_t14set_checkpointENS0_13basic_cstringIKcEEjS4_'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text+0x136): undefined reference to `_imp___ZN5boost10test_tools9tt_detail10check_implERKNS0_16predicate_resultERKNS_9unit_test12lazy_ostreamENS5_13basic_cstringIKcEEjNS1_10tool_levelENS1_10check_typeEjz'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text+0x21d): undefined reference to `_imp___ZN5boost9unit_test9ut_detail24auto_test_unit_registrarC1ENS0_13basic_cstringIKcEE'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text+0x284): undefined reference to `_imp___ZN5boost9unit_test9ut_detail24auto_test_unit_registrarC1EPNS0_9test_caseEm'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text+0x2a4): undefined reference to `_imp___ZN5boost9unit_test9ut_detail24auto_test_unit_registrarC1Ei'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text$_ZN5boost9unit_test14make_test_caseERKNS0_9callback0INS0_9ut_detail6unusedEEENS0_13basic_cstringIKcEE[__ZN5boost9unit_test14make_test_caseERKNS0_9callback0INS0_9ut_detail6unusedEEENS0_13basic_cstringIKcEE]+0x1d): undefined reference to `_imp___ZN5boost9unit_test9ut_detail24normalize_test_case_nameENS0_13basic_cstringIKcEE'
C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cciSdkmB.o:test1.cpp:(.text$_ZN5boost9unit_test14make_test_caseERKNS0_9callback0INS0_9ut_detail6unusedEEENS0_13basic_cstringIKcEE[__ZN5boost9unit_test14make_test_caseERKNS0_9callback0INS0_9ut_detail6unusedEEENS0_13basic_cstringIKcEE]+0x5b): undefined reference to `_imp___ZN5boost9unit_test9test_caseC1ENS0_13basic_cstringIKcEERKNS0_9callback0INS0_9ut_detail6unusedEEE'
collect2.exe: error: ld returned 1 exit status
I'm using g++ 4.7.2 on MinGW, with boost 1.52.0.
I get the same errors when only trying to compile test1.cpp - except the "multiple main definition" one.
I perused the official documentation for quite a while, but its scarce on details regarding linking options. When I compiled the boost libs, besides unit_test_framework, I also got prg_exec_monitor and test_exec_monitor; perhaps I should link these somehow ? I tried many combinations, but all resulted in some kind of undefined reference linker error.
Complete list of boost generated libraries - I have them all in the project root:
libboost_prg_exec_monitor-mgw47-mt-1_52.a
libboost_prg_exec_monitor-mgw47-mt-1_52.dll
libboost_prg_exec_monitor-mgw47-mt-1_52.dll.a
libboost_prg_exec_monitor-mgw47-mt-d-1_52.a
libboost_prg_exec_monitor-mgw47-mt-d-1_52.dll
libboost_prg_exec_monitor-mgw47-mt-d-1_52.dll.a
libboost_test_exec_monitor-mgw47-mt-1_52.a
libboost_test_exec_monitor-mgw47-mt-d-1_52.a
libboost_unit_test_framework-mgw47-mt-1_52.a
libboost_unit_test_framework-mgw47-mt-1_52.dll
libboost_unit_test_framework-mgw47-mt-1_52.dll.a
libboost_unit_test_framework-mgw47-mt-d-1_52.a
libboost_unit_test_framework-mgw47-mt-d-1_52.dll
libboost_unit_test_framework-mgw47-mt-d-1_52.dll.a
With help from #llonesmiz, a number of issues were identified.
1. Libraries need to be specified after objects and sources which use them.
As described here:
The traditional behavior of linkers is to search for external functions from
left to right in the libraries specified on the command line. This means that a
library containing the definition of a function should appear after any source
files or object files which use it. This includes libraries specified with the
short-cut -l option, as shown in the following command:
$ gcc -Wall calc.c -lm -o calc (correct order)
With some linkers the opposite ordering (placing the -lm option before the file
which uses it) would result in an error,
$ cc -Wall -lm calc.c -o calc (incorrect order)
main.o: In function 'main':
main.o(.text+0xf): undefined reference to 'sqrt'
because there is no library or object file containing sqrt after ‘calc.c’. The
option -lm should appear after the file ‘calc.c’
2. Library paths should be explicitly specified.
If no lib paths are specified, the linker might look for the libs in a series
of default folders, thus loading a different library then intended. This is what
happened in my case - I wanted to link boost_unit_test_framework, but did not
specify a path because I assumed the linker would look in the current folder.
That's what happens at runtime, after all - if the dll is in the same folder
with the exe, it will find it.
I found it a little bit strange the linker would find the lib, since it was
named ibboost_unit_test_framework-mgw47-mt-1_52.dll. When I tried to link to
a non-existing lib, the linker complained though, so I assumed this isn't an
issue, and MinGW 's linker ignores those suffixes.
After some more research, I found this article about MinGW library paths.
The folders MinGW searches for libs can be found in the output of gcc -print-search-dirs.
The article also contains some bash magic to make sense of that output:
gcc -print-search-dirs | sed '/^lib/b 1;d;:1;s,/[^/.][^/]*/\.\./,/,;t 1;s,:[^=]*=,:;,;s,;,; ,g' | tr \; \\012 | grep -v '^ */'
This will print a nice list of those folders. gcc will not, by default,
look in the current directory for libs. I looked in each of them, and found the
lib that was being loaded - libboost_unit_test_framework.a, a static lib.
This brings into light another issue worth mentioning:
3. Static versus dynamic linking
I did not specify whether I want boost_unit_test_framework linked statically or dynamically.
In this case, gcc prefers dynamic linking:
Because of these advantages gcc compiles programs to use shared libraries by
default on most systems, if they are available. Whenever a static library
‘libNAME.a’ would be used for linking with the option -lNAME the compiler
first checks for an alternative shared library with the same name and a ‘.so’
extension.
(so is the extension for dynamic libraries on Unix - on Windows, the equivalent is dll.)
So, what happened is that gcc looked for libboost_unit_test_framework.dll
in all it's default folders, but couldn't find it. Then it looked for
libboost_unit_test_framework.a, and statically linked that. This resulted in
linking errors because the sources have #define BOOST_TEST_DYN_LINK, and
therefore expect to have the lib dynamically linked.
To enforce static or dynamic linking, the -Wl,-Bstatic and -Wl,-Bdynamic
linker options come into play, described here.
If I tell the linker that I want dynamic linking:
$ g++ -I/e/code/boost_1_52_0 runner.cpp test1.cpp -o runner -Wl,Bdynamic -lboost_unit_test_framework
This will fail, because the linker will not be able to find the dll.
4.Summary
The issues were:
libraries where specified before the sources which used them
the lib path wasn't specified
the type of linking wasn't specified
the name of the library was not correct
Final, working command:
$ g++ -I/e/code/boost_1_52_0 -o runner runner.cpp test1.cpp -L. -Wl,-Bdynamic -lboost_unit_test_framework-mgw47-mt-1_52
SOLUTION: I just added -lpthread -ldl flags to my makefile and it works! Have no idea why, but I'm lucky enough to avoid compiling of sqlite3 by hand as I was trying.. Hmm, anyway some answers where pretty good. Thanks guys, will go and drink some tea for you.
Three months ago I was able to find how to do that but now it is not working. I have a huge C++ app, where I need to embed the sqlite3 code, but I can't compile it. I use something like this:
gcc sqlite3.c -lpthread -ldl -o ./sqlite3.o
But it does not work; I have tried a lot of variations. I have a makefile, where I added sqlite3.h and sqlite3.c files. When I do make && make install in my app's particular folder, it shows errors:
.libs/sqlite3.o: In function `pthreadMutexTry':
/home/.../client/sqlite3.c:17769: undefined reference to `pthread_mutex_trylock'
.libs/sqlite3.o: In function `pthreadMutexAlloc':
/home/.../client/sqlite3.c:17637: undefined reference to `pthread_mutexattr_init'
/home/.../client/sqlite3.c:17638: undefined reference to `pthread_mutexattr_settype'
/home/.../client/sqlite3.c:17640: undefined reference to `pthread_mutexattr_destroy'
This means that I need to add the -lpthread flag, when trying to compile sqlite3 separately from the app. Well, I am stuck.
The order of the libraries on the command line when linking matters. Put the libraries (-lpthread -ldl) last.
You need -c flag to produce an object file and not link. And skip the libraries — you pass them when linking the entire application.
gcc -c -o sqlite3.o sqlite3.c