I am compiling a program on AIX. It is compiled successfully but gives following warnings:
ld: 0711-224 WARNING: Duplicate symbol: .basename
ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information.
I tried to find this symbol I found in my "common.o" file.
nm -X64 -f common.o | fgrep '.basename'
.basename T 3776 120
But when find this symbol on executable I find following:
nm -X64 CCF | fgrep '.basename'
.basename T 4295089984 120
.basename T 4295174672
.basename t 4295174672 40
Can I display the libraries name that contains this symbol?
Does this symbol present in my source file ? (may be sound silly but I do not really know)
I have find the answer to this question that it can be traced in source.
What steps should I take to remove this warning?
Also does this duplicate symbol can cause application crash?
In my case it is crashing.
According to the man page, there are two versions of basename(), one POSIX and one GNU, and it looks like you are linking in both of them. You will need to choose one and suppress the other, depending on your needs. The man page explains how.
Because they behave differently, code that is compiled for one will likely crash when the linker/loader binds it to the other one. If you have a choice of compilers, choosing the non-gcc one might help.
Related
I've had this error for weeks I already made a post about it but it wasn't very clear.
So I am calling a function from a a header file myBmpGris.h and the functions are implemented on the file myBmpGris.c . Here is my main file:
#include<stdio.h>
#include<stdlib.h>
#include "myBmpGris.h"
int main(){
char * image_name = "image_carre.bmp";
BmpImg image = readBmpImage(image_name);
return 0;
I compile by using ggc main.c and I get this error message :
Undefined symbols for architecture x86_64:
"_readBmpImage", referenced from:
_main in main-1c453a.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I read a lot of posts about the same error message but none of the answers seem to apply to my case. I'm kind of desperate because a lot of my programs give me the same error. What should I do ?
You need to tell the compiler about all the code files which contain any of the needed functions.
So if you have until now compiled like gcc main.c, then the simplest way of also getting the other file compiled is gcc main.c myBmpGris.c.
You might want to read up on the other things you can helpfully tell the compiler (and other parts of the building), i.e. the possible commandline parameters. Or use one of the available free programming environments. (I am not going to name any. Just use your favorite search engine on "C IDE free" or similar. The first few hits discuss several, try a few, then use the one your friends use, or the one you really like much, much better.)
There are two thing.
Compilation you have included. h file. It means comilper will make entry in symbol table for all used function from included library.
Linking here linker try to get address from library to fill in symbol table created in first step. This cannot be performed in your case. So give full path of library.
I'm compiling a C++ static library using g++ via Cmake. I want to remove symbols relating to the internal implementation so they don't show up in nm. (See here and here for the same with shared libraries.)
This answer tells you how to do it on iOS, and I'm trying to understand what happens under the hood so I can replicate on Linux. They invoke ld with:
-r/--relocatable to Generate relocatable output---i.e., generate an output file that can in turn serve as input to ld.
-x/--discard-all: Delete all local symbols.
AFAICS the -r glues all the modules into one module, and then the -x removes symbols only used inside that module. Is that right?
It's not clear how the linker 'knows' which symbols will be exported externally? Does it rely on __attribute__((visibility("hidden/default"))) as in the .so case?
Edit: clearly I'm confused... I thought cmake invoked ld to link the .os into .a. Googled + clarified above.
Question still stands: how do I modify the build process to exclude most symbols?
Now I am writing a program to call a web service. I write testMain.c. The others are generated by wsdl2h and soapcpp2.
My compiling command is like this:
gcc -Wall -g -c -L. soapC.c soapClient.c stdsoap2.c testMain.c
gcc -o testMain -L/usr/lib -lgsoap -lgsoapck -lgsoapssl soapC.o soapClient.o stdsoap2.o testMain.o
And I get these errors. Please help me.
stdsoap2.o: In function `soap_print_fault':
/test/stdsoap2.c:16279: undefined reference to `soap_check_faultsubcode'
/test/stdsoap2.c:16281: undefined reference to `soap_check_faultdetail'
stdsoap2.o: In function `soap_sprint_fault':
/test/stdsoap2.c:16341: undefined reference to `soap_check_faultdetail'
collect2: ld returned 1 exit status
Recent versions of GCC/ld/the GNU toolchain require that the object and library files be specified in a certain order, so that symbols can be found by the linker in the same order they depend on each other. This means that libraries should go to the end of the command line; your second line (when you're linking) should be
gcc -o testMain -L/usr/lib soapC.o soapClient.o stdsoap2.o testMain.o -lgsoap -lgsoapck -lgsoapssl
instead.
I search the web, and found a post which is very similar with my problem. I use this solution and have solved the problem. http://www.mail-archive.com/gsoap#yahoogroups.com/msg01022.html
You should not need to link stdsoap2.o to your project because it's already included in libgsoap (given through the gcc linker option -lgsoap). Try to exclude stdsoap2.c from your project. From the gSOAP FAQ:
I get a link error with gcc/g++ (GNU GCC). What should I do? For C
apps: use soapcpp2 option -c to generate C code, use only the
package's .c files, link with libgsoap.a (-lgsoap) or use the lib's
source stdsoap2.c (and dom.c when applicable).
I had the same problem with gsoap-2.8.16 compiled from source. (That version was shipped with CentOS 6.)
First I checked for a missing library. According to nm used on all static libraries provided by gsoap-2.8.16:
for X in /usr/local/lib/libgsoap*.a ; do echo $X; nm $X | grep soap_check_faultdetail; done`
it turned out that none of the libraries provided the missing symbols.
A brief look at the source code revealed that the expected return type of both methods soap_check_faultdetail and soap_check_faultsubcode was const char*, and that these were used to generate error messages.
It looked to me as if these are meant to be callbacks that the client must provide. Maybe their implementation is WSDL-dependent and would be supplied by the gsoap code generation utilities - that I don't know, see the answer from #ChristianAmmer above or below.
Anyway, since I knew the symbols were nowhere supplied, and that null-terminated strings were probably acceptable here, I just supplied my own no-op implementation:
// gsoap-missing-symbols.cpp
extern "C" {
const char* soap_check_faultdetail() { return 0; }
const char* soap_check_faultsubcode() { return 0; }
}
This is a brute-force solution. If you follow this solution, you should maybe check for linker warnings in the future; maybe some mechanism (eg. from the gsoap code generator) will supply conflicting implementations later during development.
For later versions of gsoap, I believe these symbols are no longer used and can be dropped (or renamed), see soap_check_faultX in https://www.genivia.com/changelog.html.
I am trying to compile a program written in c using the expect.h header. I am trying this:
cc -I/usr/include main.c -lexpect -ltcl
cc -I/usr/include main.c
I tried the same with gcc, but to no avail.
I get this:
undefined reference to `exp_spawnl'
undefined reference to `exp_expectl'
Any ideas?
Thanks,
Walter
It means that regardless of what you thought was being used, the expect library being used does not contain those two functions. So, you need to track down which expect library is actually loaded, and then check whether the functions are in it (they aren't, but you should check to see what is defined).
Once you've found your library, you can use nm -g libexpect.so to see the symbols defined. I would expect that you will not see exp_spawnl or exp_expectl in the list of defined symbols.
Then you need to find out which version of the library you do have, and decide whether to upgrade, etc.
I am assuming that the names you quote are indeed spelled correctly.
Is the expect header file installed in /usr/include?
I think the undefined reference error comes from the linker and not the compiler. What directory is the library installed to? Try to link against it using the
-L/path/to/lib -lexpect
option
Getting a linker error on osx (no errors on linux or fbsd for the same code):
ld: duplicate symbol _dbg_char in .libs/liboekernel_la-OEK_get.o and .libs/liboekernel_la-OEK.o
the 2 libs listed in the error are mine but the symbol isn't. c++flint confirms '_dbg_char' is in both libs but I'm not sure how to find where it comes from.
tricks, strategies, outright answers for how to id _dbg_char would be greatly appreciated.
project is using libtool/autotools and gcc 4.01
Found a logging / debug macro that was defining dbg_char by 'dbg_ ## t'. fix was to make it static. lessons learned:
osx adds a leading _ to symbol names. it wasn't until i ran nm on linux and saw the same symbol without the leading _ that i thought to search the codebase for "dbg_" instead of "_dbg_"
osx was right to complain
rich irony that cut-and-pasting a debug macro i didn't fully understand caused me so much trouble
You might want to check if both libs #include a header file that declare _dbg_char but miss the extern keyword. Maybe that's #ifdef 'ed out for other platforms so you only hit that problem on OS X.