I am trying to compile and having following problem
$ gcc errlib.c -o errlib.o
/usr/lib/gcc/x86_64-pc-cygwin/4.8.2/../../../../lib/libcygwin.a(libcmain.o): In function `main':
/usr/src/debug/cygwin-1.7.30-1/winsup/cygwin/lib/libcmain.c:39: undefined reference to `WinMain'
/usr/src/debug/cygwin-1.7.30-1/winsup/cygwin/lib/libcmain.c:39:(.text.startup+0x7e): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `WinMain'
collect2: error: ld returned 1 exit status
Any suggestions? These files are well tested and generated the code fine before but now i think there might be some cygwin settings or so ... m compiling on windows 8 on cygwin.
Use -c compile flag to only produce object file. Without -c it tries to link an executable and the linker (called automatically) fails.
Related
I'm trying to develop a small utility using the dialog library in C (the dialog command in linux).
On fedora linux works fine, but if i try to compile it on debian with the command:
gcc -ldialog -lncurses -I/usr/include dialog_test.c
I get the following error:
vetinari#ankhmorpork:~/Projects/Other/test$ gcc -ldialog -I/usr/include dialog_test.c
/usr/bin/ld: /tmp/ccX6fPYB.o: warning: relocation against `dialog_vars' in read-only section `.text'
/usr/bin/ld: /tmp/ccX6fPYB.o: in function `main':
dialog_test.c:(.text+0x5c): undefined reference to `init_dialog'
/usr/bin/ld: dialog_test.c:(.text+0x79): undefined reference to `dialog_yesno'
/usr/bin/ld: dialog_test.c:(.text+0xae): undefined reference to `dialog_menu'
/usr/bin/ld: dialog_test.c:(.text+0xbc): undefined reference to `dialog_vars'
/usr/bin/ld: dialog_test.c:(.text+0xc5): undefined reference to `end_dialog'
/usr/bin/ld: warning: creating DT_TEXTREL in a PIE
collect2: error: ld returned 1 exit status
The dialog command works fine.
Anyone has any idea why it isn't working on debian?
(Answer for the wiki sake, in case someone comes by here later)
You have to put the libraries you want to link at the end of the gcc command, like this:
gcc dialog_test.c -ldialog -lncurses
The reason is explained here: The way the linker looks up symbols it has to first see the reference, and then the library prodiving the symbol
Additionally, the dialog library might have other dependencies than ncurses. There is explanation how to find out what to include and what to link here, in short: dialog-config should tell you about it.
In this specific case, what worked for me (ubuntu 20.04) was linking ncursesw instead of ncurses.
After that, I was left with an
undefined reference to `sqrt'
linker error, which can be solved by linking the match library using -lm.
So, in total, this command works:
gcc dialog_test.c -ldialog -lncursesw -lm
On Ubuntu 14.04, I'm trying to do a small example of bluetooth device listing but I'm facing a simple issue about linking with the bluetooth shared library when compiling this minimalistic demo http://people.csail.mit.edu/albert/bluez-intro/c404.html:
$ sudo apt-get install libbluetooth-dev
$ gcc -lbluetooth simplescan.c -o simplescan
/tmp/ccuwRsB5.o: In function `main':
simplescan.c:(.text+0x79): undefined reference to `hci_get_route'
simplescan.c:(.text+0x8c): undefined reference to `hci_open_dev'
simplescan.c:(.text+0x132): undefined reference to `hci_inquiry'
simplescan.c:(.text+0x18f): undefined reference to `ba2str'
simplescan.c:(.text+0x1f0): undefined reference to `hci_read_remote_name'
collect2: error: ld returned 1 exit status
$ nm -D /usr/lib/x86_64-linux-gnu/libbluetooth.so.3.13.0 | grep hci_get_route
0000000000008f00 T hci_get_route
The bluetooth shared library seems to be found and containing the required functions, but the linking phase doesn't achieve.
The solution is astonished (to me): the order of the arguments given to gcc is important. "-lbluetooth" should be put after "simplescan.c":
$ gcc simplescan.c -lbluetooth -o simplescan # Success
$ gcc -lbluetooth simplescan.c -o simplescan # Failure
/tmp/ccWhZFXs.o: In function `main':
simplescan.c:(.text+0x79): undefined reference to `hci_get_route'
simplescan.c:(.text+0x8c): undefined reference to `hci_open_dev'
simplescan.c:(.text+0x132): undefined reference to `hci_inquiry'
simplescan.c:(.text+0x18f): undefined reference to `ba2str'
simplescan.c:(.text+0x1f0): undefined reference to `hci_read_remote_name'
collect2: error: ld returned 1 exit status
On ubuntu-13.04, I got an error when building an executable from shared libraries, using GCC-4.7.3 provided by the linux distribution.
I guess the problem is between libpng and zlib (the former uses the latter), but I don't know why.
First, my command is:
$ gfortran -o test_muesli_config_fml test_muesli_config_fml.o -fopenmp
-Wl,--rpath,/usr/local/lib/muesli /usr/local/lib/muesli/libfml.so -lstdc++
-Wl,--rpath,/usr/lib /usr/lib/liblapack.so -Wl,--rpath,/usr/lib /usr/lib/libblas.so
-lpng -lz -lpthread -lreadline -lhistory
which gives the following error:
/usr/local/lib/muesli/libfml.so: undefined reference to `gzwrite'
/usr/local/lib/muesli/libfml.so: undefined reference to `gzopen'
/usr/local/lib/muesli/libfml.so: undefined reference to `gzclose'
/usr/local/lib/muesli/libfml.so: undefined reference to `gzread'
collect2: error: ld returned 1 exit status
But note that -lz is present. After that, I added the linker option --trace-symbol= in order to get more information:
$ gfortran -o test_muesli_config_fml test_muesli_config_fml.o -fopenmp
-Wl,--rpath,/usr/local/lib/muesli /usr/local/lib/muesli/libfml.so -lstdc++
-Wl,--rpath,/usr/lib /usr/lib/liblapack.so -Wl,--rpath,/usr/lib /usr/lib/libblas.so
-lpng -lz -lpthread -lreadline -lhistory -Wl,--trace-symbol=gzwrite
which in turn gives the results:
/usr/local/lib/muesli/libfml.so: reference to gzwrite
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libz.so: definition of gzwrite
/usr/local/lib/muesli/libfml.so: undefined reference to `gzwrite'
/usr/local/lib/muesli/libfml.so: undefined reference to `gzopen'
/usr/local/lib/muesli/libfml.so: undefined reference to `gzclose'
/usr/local/lib/muesli/libfml.so: undefined reference to `gzread'
collect2: error: ld returned 1 exit status
so, gzwrite is found in libz.so but the linker don't use it!
By chance, I thought to remove the -lpng option (actually, the libpng library is not used) and my problem is solved! Why?
Secondly, I compile my whole code with another version of GCC-4.7.3 (compiled by myself -- I am used to test many versions of the compiler), and the error didn't occur, even using both -lpng and -lz!
Any idea?
In addition, a different try with another program (which USE libpng) leads to a successful build.
Edited on 2013-10-08
I'm pretty sure now that it is a bug in ubuntu-13.04: I've tried two other linux distros (Fedora 16 -- Ubuntu-10.04) and the linker behavior is standard, not as described above in the first part of my message.
I plan to report this problem on ubuntu community. Regards.
Edited on 2013-10-09
The bug has been reported to https://bugs.launchpad.net/ubuntu/+source/gcc-defaults/+bug/1237270
Two possible fixes (until ubuntu doesn't repair itself):
Try to compile in libpng.a and libz.a as a static library (it can be only a temporary solution, because static libs are evil in most cases).
Recompile libpng from the original source, and compile libz.a as static herein.
I am trying to compile a v4l2 example in Ubuntu but I am getting the following error:
guilherme#notedev01:~/Downloads/V4l2_samples-0.4.1$ make
gcc -O2 -L/usr/include -lX11 -lXext -o viewer viewer.c
/tmp/ccUjnjWQ.o: In function `image_destroy':
viewer.c:(.text+0x234): undefined reference to `XDestroyImage'
viewer.c:(.text+0x256): undefined reference to `XFreeGC'
viewer.c:(.text+0x277): undefined reference to `XShmDetach'
viewer.c:(.text+0x2ac): undefined reference to `XFreePixmap'
/tmp/ccUjnjWQ.o: In function `image_create':
viewer.c:(.text+0x305): undefined reference to `XCreateGC'
viewer.c:(.text+0x31d): undefined reference to `XGetWindowAttributes'
viewer.c:(.text+0x39e): undefined reference to `XShmCreateImage'
viewer.c:(.text+0x3f5): undefined reference to `XShmAttach'
viewer.c:(.text+0x44e): undefined reference to `XCreateImage'
viewer.c:(.text+0x494): undefined reference to `XShmQueryExtension'
viewer.c:(.text+0x4b4): undefined reference to `XShmPixmapFormat'
viewer.c:(.text+0x4dc): undefined reference to `XShmCreatePixmap'
/tmp/ccUjnjWQ.o: In function `image_put':
viewer.c:(.text+0x54c): undefined reference to `XPutImage'
viewer.c:(.text+0x586): undefined reference to `XShmPutImage'
/tmp/ccUjnjWQ.o: In function `main':
viewer.c:(.text.startup+0x18b): undefined reference to `XOpenDisplay'
viewer.c:(.text.startup+0x1b1): undefined reference to `XScreenOfDisplay'
viewer.c:(.text.startup+0x1ee): undefined reference to `XCreateSimpleWindow'
viewer.c:(.text.startup+0x249): undefined reference to `XMapRaised'
viewer.c:(.text.startup+0x263): undefined reference to `XStoreName'
viewer.c:(.text.startup+0x280): undefined reference to `XGetWindowAttributes'
viewer.c:(.text.startup+0x92f): undefined reference to `XPending'
viewer.c:(.text.startup+0x94c): undefined reference to `XNextEvent'
viewer.c:(.text.startup+0xaee): undefined reference to `XPending'
viewer.c:(.text.startup+0xb0b): undefined reference to `XNextEvent'
viewer.c:(.text.startup+0xf39): undefined reference to `XPending'
viewer.c:(.text.startup+0xf56): undefined reference to `XNextEvent'
collect2: error: ld returned 1 exit status
make: *** [viewer] Error 1
What I can see is that the path for -lx11 and -lXext isn't -L/usr/include.
How can I find the right path for those libraries?
Thanks.
as Chris has pointed out, the order is wrong, you need to put the -lX11 -lXext after the source-code/object-files.
this is because modern compilers try to optimize the final result and not link against unused libraries.
they do so by maintaining a list of unresolved symbols within an object and use any binary files that come aferwards in the linker arguments to resolve those symbols.
example
your program test uses the function do_foo() from libfoo and the function do_bar_do() from libbar.
you link it using:
$ gcc -o test test.o -lfoo -lbar
the linker first searches test.o and notices that some symbols (do_foo and do_bar_do) are not defined anywhere. it then proceeds to libfoo (specified right after test.o) and finds that it provides do_foo, so it creates code to use it from your program. do_bar_do is still unresolved, until the linker checks upon libbar.
consider doing it the wrong way:
$ gcc -o test -lfoo test.o -lbar
the linker will first check libfoo and see that it doesn't contain any unresolved symbols. cool. it will then proceed to test.o and notice do_bar_do and do_foo. do_bar_do is resolved by the right-hand libbar but do_foo is not resolved at all, and you get an error:
undefined reference to `do_foo'
"but the code is meant to be a tutorial..."
so why is it not working?
older compilers where a bit lax about the order of dependencies (they would check all binaries/libraries/objects whether a given symbol could be resolved); that's why you can still find code out there that puts the libraries to link against before the object files.
The -lX11 -lXext must come after the viewer.c in the command line (and should probably be in the order -lXext -lX11). Also, ensure that the libx11-6-dev and libxext6-dev packages are installed.
System libraries are usually in /lib and /usr/lib, and you do not need to use -L to specify those directories.
I need your help about this problem if anyone has info.
I have configured speex1.2rc1 for xscale-elf (ARM architecture) ,then executed make and make install. So, I obtained libspeex.a in the /usr/local/lib with libogg.a compiled as well. but i when i link the library to my program (by adding LDFLAGS += -lspeex -lm), and try to compile, i get this error:
/usr/lib/gcc/xscale-elf/3.4.3/../../../../xscale-elf/bin/ld: cannot find -lspeex
collect2: ld returned 1 exit status
make: *** [exe0] Error 1
I passed ./configure options as :
./configure --host=xscale-elf
It's likely that the linker can't see libspeex.a, and I also tried the line LDFLAGS += /usr/local/lib/libspeex.a -lm in Makefile but got another error(also in linking):
/tmp/ccvi7Pns.o(.text+0x179c): In function `main':
: undefined reference to `BlinkC$speex_bits_init'
collect2: ld returned 1 exit status
make: *** [exe0] Error 1
./configure --host=xscale-elf
You didn't tell what host you are compiling this on, but given the path to your ld, it appears that you are cross-compiling. If so, your host is likely not xscale-elf (but probably i686-linux-gnu or some such).
You need to understand the difference between host and target, and rebuild your speex1 (whatever that is) using appropriate compiler and --target=xscale-elf.
Also, installing libraries intended for taget into /usr/local/lib is the wrong thing to do.