I tried to link an existing C++ library to go code. The C++ library only has a static library and a header file, no source code.
I used swigc to generate a libfoo.go and I wrote a simple libb.go to build this library. This worked well on ubuntu 16.04 with gcc-6 earlier.
However, once I upgraded to ubuntu 18, and even with older go1.9 and gcc-6, which used to work, I am hitting the following error:
/usr/bin/ld: ./lib/libfoo.a(parser.o): relocation R_X86_64_32S against symbol `xmlSAX2IgnorableWhitespace' can not be used when making a PIE object; recompile with -fPIC
/usr/bin/ld: ./lib/libfoo.a(tree.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a PIE object; recompile with -fPIC
I have downgraded both go compiler and gcc to the version that used to work.
The following is the libb.go that used to work
/*
#cgo CXXFLAGS: -std=c++11 -D_GLIBCXX_USE_CXX11_ABI=0 -w
#cgo CFLAGS: -I${SRCDIR}/include -w
#cgo LDFLAGS: -Wl -rpath,./lib, -L${SRCDIR}/lib -l:libfoo.a -l:libxml2.a
*/
import "C"
What should I do get this fixed? I searched and it seems that I have to recompile that static library, which is mission impossible in my case. I tried to pass the -no-pie parameter to LDFLAGS, that didn't work either.
I also run into this problem these days. Finally, I found that adding below lines
"env CGO_LDFLAGS=-no-pie"
to go build command line could solve this problem. For example,
"env CGO_LDFLAGS=-no-pie go build -o main main.go"
Related
I am currently building a shared library (lib1.so) out of a cmake environment.
lib1.so depends on an external static lib libLASlib.a (which I am able to recompile if necessary).
Everything works wonder on windows so far, but it's another story when switching to linux:
/usr/bin/ld: lib/LASlib/libLASlib.a(lasreader.cpp.o): relocation R_X86_64_PC32 against symbol `_ZN9LASreader35read_point_filtered_and_transformedEv' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
So I tried recompiling the libLASlib with -fPIC -> same error
Due to my environment I could not verify the fpic was effectivelly added to the gcc command line.
Here is what I tried to confirm there was no issue with the fPIC:
readelf --dynamic libLASlib.a | grep lasreader.cpp.o -A2
File: libLASlib.a(lasreader.cpp.o)
There is no dynamic section in this file.
For the record not a single cpp.o was found with a dynamic section
I have tried just to see what it would give if i changed liblas from a static to a shared library -> no error
Any thoughs?
Many thanks!
You need to compile lasreader.cpp with -fPIC. Something like this:
g++ -c -fPIC -o lasreader.cpp.o lasreader.cpp
The fPIC was indeed not applied
Conan doesn't seem to forward the fPIC option
I edited the CMAKELIST and added
set_property(TARGET LASlib PROPERTY POSITION_INDEPENDENT_CODE ON)
And it eventualy passed
I recently upgraded gSOAP from 2.8.7 to 2.8.76. I had to make a few minor code adjustments for the upgrade, but after the upgrade the code won't link on the computer it would before.
I'm trying to use gSOAP to create a shared library on a computer which uses g++ 4.9.2. I've condensed the code down to create a test case that simplifies things a bit to try to identify where the failure is occurring.
gSOAP generates some ebaySoapLib* files when I run:
/usr/local/bin/soapcpp2 -z1 -C -w -x -n -pebaySoapLib -qebaySoapLib -I/usr/local/include/gsoap:/usr/local/share/gsoap:/usr/local/share/gsoap/import ebaySvc.h
The -z1 option is to keep things similar to how they were with gSOAP 2.8.7.
If I run:
g++ -fPIC -c ebaySoapLibClientLib.cpp
g++ -shared -fPIC -o test.so ebaySoapLibClientLib.o
I get the error:
/usr/bin/ld: ebaySoapLibClientLib.o: relocation R_X86_64_PC32 against
undefined symbol `soap_serializeheader' can not be used when making a
shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
I copied over the exact files to another computer running g++ 6.3.0 (not sure that the compiler version is what is mattering or now), and this compiles and links fine.
The file ebaySoapLibClientLib.cpp contains:
#define SOAP_FMAC3 static
#include "ebaySoapLibC.cpp"
#include "ebaySoapLibClient.cpp"
Now, if I remove the line:
#define SOAP_FMAC3 static
then the code compiles fine on both computers.
I'm at a loss for what I need to do differently to make it link OK with the g++ 4.9.2 computer. I could take out the #define so the functions aren't defined static and get it to work, but the question is WHY as gSOAP is putting it in there for a reason, and it links fine on the g++ 6.3.0 with these functions set to static.
You need to get library that supplies soap_serializeheader to be compile ready for shared library, its not ebaySoaLibClientLib.cpp. Use g++ -v to see what libraries g++ is using. Try using shared library instead of static ones.
I am using the command:
g++ --std=c++11 -fPIC -Iincludes parser.cpp lib/main-parser.o lib/lib.a
To compile a C++ program on Debian 9. But I am getting the below error message:
/usr/bin/ld: lib/lib.a(csdocument.o): relocation R_X86_64_32 against '.rodata' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Nonrepresentable section on output
collect2: error: ld returned 1 exit status
I have already seen the thread:
Compilation fails with "relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object"
However, I have tried adding the -fPIC argument however it strangely gives the same error message, along with "recompile with -fPIC"
Any ideas would be appreciated. I have tried compiling this on my University's RedHat systems and it works fine there. I'm thinking it could be a missing dependency, but I've been unable to find any answers.
Thanks in advance
As it seems gcc is trying to produce a position-independent executable ("shared object" is the hint), tell it not to:
g++ --std=c++11 -no-pie -Iincludes parser.cpp lib/main-parser.o lib/lib.a
It seems that g++ produces position-independent executables by default on your system. Other systems would require -pie to do so. Using -no-pie should create a "regular" (position dependent) executable.
(The error is a result of trying to link an object file that was compiled as non-position-independent into an executable that is supposed to be position-independent).
/usr/bin/ld: lib/lib.a(csdocument.o): relocation R_X86_64_32 against '.rodata' \
can not be used when making a shared object; recompile with -fPIC
This linker error is telling you that the object file csdocument.o in the
static library lib/lib.a is not Position Independent Code and hence
cannot be linked with your PIE program. So you need to recompile the source
files of lib/lib.a with -fPIC, then rebuild the static library, then link
it with your PIE program. If you don't have control of the libary sources
then request a PIC build from its supplier.
(Others have questioned why you should need to build a PIE target at all
since it's not a shared library. In Debian 9, GCC produces PIE executables
by default,
whether programs or shared libraries. The same goes for Ubuntu as of 17.04. )
Adding this worked for me.
g++ --std=c++11 -no-pie
I also added the -fPIC to compile flag.
I have a Shared Library Project which builds only if I add -fPIC to the Compiler command ( this solves the issue ).
When I try to use a static library in this project I get a similar issue but in this situation I cannot fix with -fPIC:
libtest.a(exception.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
Could I get some help please on how I can link this successfully ? I've tried adding -fPIC to the linker option also but I get the same error.
I am using GCC Compiler on Linux.
From the question it appears you are updating the link time to add -fPIC, but you need to recompile libtest.a with -fPIC so that the relocations created in exception.o and the other objects in the library are PIC compatible.
I am trying to use the libsodium library in a C++ project and I'm having difficulty with linking the static Libsodium Library into a Shared Object that I've created. This project is being compiled using G++ and is set to use C++11 Standards.
After reading various forum posts about linking a Static Library into a Shared Object, I've tried using the Whole Archive which seems to get me further but still will not link in correctly.
The following is the Command being used to link:
/usr/bin/g++ -shared -fPIC -o ./Debug/libwowcrypt.so #"libwowcrypt.txt" -L. -L../SharedLibraries/Sodium/lib -Wl,--whole-archive -lsodium -Wl,--no-whole-archive
The following error messages are returned from ld:
/usr/bin/ld: ../SharedLibraries/Sodium/lib/libsodium.a(libsodium_la-hmac_hmacsha256.o): relocation R_X86_64_PC32 against symbol `crypto_auth_hmacsha256_init' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
Can anyone advise on the correct linker flags that are needed to incorporate this static library into my shared object?
I ran into the same problem. Assuming you are on Ubuntu < 15.04 (mine is 14.04 LTS), you need to disable PIE
./configure --disable-pie
and then the usual: make / make install etc.
Now you should be able to link the static libsodium.a to your .so. I got this from a recent discussion on github issue i raised here