I need to include libexplain to my project to do certain job. I install it and add the header libexplain/read.h to my code, so far so good and no error reported by the complier. But when I use the function explain_read() provided by libexplain and build the project it says:
/tmp/cc7NjAw0.o: In function `xl45_read(int, unsigned char*)':
connections.cpp:(.text+0x2f): undefined reference to `explain_read'
collect2: error: ld returned 1 exit status
and the build script is:
#!/bin/bash
echo > ./stdafx.h
g++ -O1 -Wall -o ./local_proxy (*.cpp...here is the source file list) -lz -lpthread -lpcap -L/usr/local/lib
actually when I type
whereis libexplain
in terminal, I get
libexplain: /usr/lib/libexplain.so /usr/lib/libexplain.a /usr/include/libexplain
I do a lot of searches and still have no idea what's going wrong. ):
You need to link your object files with libexplain. You can do it using the -l<library name>, like so:
g++ -O1 -Wall -o ./local_proxy *.cpp -lz -lpthread -lpcap -lexplain -L/usr/local/lib
Note the -lexplain flag. For a library with the a file name like libABC.so, you'd use -lABC to refer to that library. The documentation for link options with GCC can shed more light on it.
Related
I am new to the command line and I am trying to run a C program containing the function log10.
If I give
gcc -o -lm randomVamp random\ vampire.c
I get the error
gcc: error: randomVamp: No such file or directory
but randomVamp is the name I wanted to give to the executable, of course it doesn't exist yet.
If I prompt just
gcc -o -lm random\ vampire.c
then I get the error
/usr/bin/ld: /tmp/ccbWivPU.o: in function `main':
random vampire.c:(.text+0x312): undefined reference to `log10'
collect2: error: ld returned 1 exit status
Anyone knows what's going on?
I don't know if it's relevant, but the program also includes stdlib.h and time.h should I use some flag or link them in some way?
-o means that the next argument is the output file name. Replace -o -lm randomVamp with something like -o randomVamp -lm.
Also, note that -l... have no effect if specified before the .c/.cpp/.o/... files. So, the command could look like this:
gcc -o randomVamp random\ vampire.c -lm
I have a problem compiling the following line of code :
gcc -o main.c -ldl -lpthread -lRTU_Module main.o
I have the following error message :
/usr/bin/ld: cannot find -lRTU_Module
collect2: error: ld returned 1 exit status
When i try to find the location of my .so it returns this :
locate libRTU_Module.so
/home/owasys/workspace/AccelTest/libRTU_Module.so
/home/owasys/workspace/Compiler_gcc-linaro-5.3_patch/files/lib/libRTU_Module.so
/home/owasys/workspace/Compiler_gcc-linaro-5.3_patch/files/lib/libRTU_Module.so.1.0.11
/opt/gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf/arm-linux-gnueabihf/libc/lib/libRTU_Module.so
/opt/gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf/arm-linux-gnueabihf/libc/lib/libRTU_Module.so.0
/opt/gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf/arm-linux-gnueabihf/libc/lib/libRTU_Module.so.0.0.0
/opt/gcc-linaro-5.3-2016.02-x86_64_arm-linux-gnueabihf/arm-linux-gnueabihf/libc/lib/libRTU_Module.so.1.0.11
I have red multiple of answer to a similar question but i have not solve my problem.
Thank you.
ld normally scans a default/configured set of dirs, generally wouldn't know about custom stuff like /home/a/b/c
Should be easy enough to fix; does this work?
dir=/home/owasys/workspace/Compiler_gcc-linaro-5.3_patch/files/lib
gcc -o main.c -ldl -lpthread -lRTU_Module.so main.o -L $dir
May need to tell the runtime link editor to search there as well, eg adding this to gcc cmd-line:
-Wl,-rpath=$dir
I have the following .sh file (from here).
g++ -c -pipe -g -std=gnu++11 -Wall -W -fPIC -I. -I./tensorflow
-I./tensorflow/bazel-tensorflow/external/eigen_archive -I./tensorflow/bazel-tensorflow/external/protobuf/src -I./tensorflow/bazel-genfiles -o main.o ./main.cpp
g++ -o Tutorial main.o -L./tensorflow/bazel-bin/tensorflow
-ltensorflow_cc
cp ./tensorflow/bazel-bin/tensorflow/libtensorflow* .
When I try to run this .sh file from terminal I got an error. Therefore I executed the commands one by one. First one worked fine and I saw that when I run the second command ( g++ -o Tutorial main.o -L./tensorflow/bazel-bin/tensorflow
-ltensorflow_cc) I get the following error.
/usr/bin/ld: main.o: undefined reference to symbol '_ZN10tensorflow3Env19NewRandomAccessFileERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEPSt10unique_ptrINS_16RandomAccessFileESt14default_deleteISA_EE'
libtensorflow_framework.so: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
I saw the answer here and I see it as closely related to mine. But I cannot figure out how to adapt it to my problem.
Can someone please help with this?
The linker is saying that the linkage requires shared library libtensorflow_framework.so (presumably because -ltensorflow_cc depends on it and requests it) but is not given in your commandline. This should be solved by adding -ltensorflow_framework at the end, with an additional -L option if necessary.
I was too getting the same error.
If you are using tensorflow 2, then you need to link .so.2 files. You should find them in the bazel build directory. For me it is :
/tmp/bazel/output/execroot/org_tensorflow/bazel-out/k8-opt/bin/tensorflow
I linked the files using the below in my CMAKE:
file(GLOB LIBRARIES "${bazel_bin}/tensorflow/*.so.2")
message("LIBRARIES = ${LIBRARIES}")
I have static library lib.a and in all tutorials using:
gcc -o main main.o -L. -lib
But I cant, I have errors:
/usr/bin/ld: cannot find -lib
collect2: error: ld returned 1 exit status
I need to use:
gcc -o main main.o -L. -lib.a
Why? What should I do to repair it ?
From the documentation of gcc -l:
-llibrary:
The linker searches a standard list of directories for the library, which is actually a file named liblibrary.a. The linker then uses this file as if it had been specified precisely by name.
...
The only difference between using an -l option and specifying a file name is that -l surrounds library with ‘lib’ and ‘.a’ and searches several directories.
So you cannot use -l with a library named 'lib.a'. Use 'lib.a' without the -l to include it. Of course, you cannot use -L then to set the directories to be searched for this particular library.
Do you have the error with this line ?
gcc -o main main.o -L. -llib
As MicroVirus found in the documentation, you will have to rename your library in liblib.a to use my previous line or just pass your library to gcc like a simple file.
I find a problem in the linking process of my application. I did not have the same with gcc 4.5. It tries to link math library with the following command.
gcc -Wall -Wno-unused -MD -o mems_seektest mems_seektest.o -lm -L. -g -DASSERTS -I../src// -I../ -I../src//src -DDEBUG -lmems_internals
and report following error massages:
undefined reference to `sqrt'
Any idea ?
recent gcc/ld uses the --as-needed linker flag as default. Practically, that means libraries have to be specified in the reverse order of dependencies on the command line. If the mems_internals library needs the sqrt function your -lm after -lmems_internals.
gcc -Wall -Wno-unused -MD -o mems_seektest mems_seektest.o -L. -g -DASSERTS -I../src// -I../ -I../src//src -DDEBUG -lmems_internals -lm
I've had the same problem with gcc 4.6.1, even with only one library. This doesn't work:
$ gcc -lm eg.o -o eg
eg.o: In function `foo':
/home/nick/tmp/eg.c:5: undefined reference to `sqrt'
collect2: ld returned 1 exit status
But this does:
$ gcc eg.o -o eg -lm
I hit this because I was using "LDFLAGS=-lm" in my Makefile. Works fine if you use "LDLIBS=-lm" instead.
You didn't tell us what -lmems_internals is, but maybe the unresolved symbol comes from there. The order of the -l options is generally important to the linker, you should always put system libraries last.
You can check where the unresolved symbol comes from by using something like
nm yourLibrary | grep sqrt
if there is a U in front of sqrt the symbol is undefined.
I'd say the linker is using the wrong libm.