I have several binaries compiled with gcc/g++ and others compiled with clang/clang++.
So far i have tried:
strings -a ./myBinary | grep -i clang
objdump -s --section .comment ./myBinary
readelf -p .comment ./myBinary
and each one of this command fails to recognize the binaries produced by clang, and each file produced by Clang is recognized as produced by gcc and basically all my binaries are produced by the same compiler according to this tools.
Does Clang puts the same signature as GCC ? How i can get informations about what compilers have generated that binaries ?
Thanks.
I guess it's a duplicate of stackoverflow.com/questions/43523698/clang-appears-to-use-gcc
It seems that if you link against a glibc built by GCC, the latter takes the credits.
Related
In my makefile I have:
g++ -o Out Out.o -I Headers_Directory -L Libraries_Directory -lFile1 -lFile2
In my Libraries_Directory I have two files libFile1.a and libFile2.so
ld finds libFile1.a but cannot find libFile2.so. How that is possible and how can I resolve the issue?
I am compiling in Cygwin and using GNU gcc-g++ compiler.
A minimalist that regenerates the error:
Download the Linux Version of Gurobi here. Then, install the software using this instruction. You need to activate the software by obtaining a license from here. Free academic license for research purpose is available. Finally navigate to the following folder
installation_directory/gurobi701/linux64/examples/build
and issue the command make. You have to compile on Cygwin with GNU gcc-g++ compiler.
I am trying to build SLitrani on Ubuntu 12.04 64-bit. I have already built ROOT 5.34.03 from source and I did figure out how to set the LD_LIBRARY_PATH and PATH variables for $ROOTDEV so the problem is not there but when I try to make SplineFit I get
>>> g++: error: unrecognized option ‘-soname=libSplineFit.so’
make: *** [libSplineFit.so] Error 1
I also did change all the -m32 to -m64 in the Makefiles so I don't know what is going on. I was able to get TwoPad installed but I can't continue from SplineFit. I have been on this build for quite some time and would appreciate any help.
From memory, soname is a linker operation, not a compiler one. So, if you're doing it with g++, you may need to change the option into something like:
-Wl,-soname=libSplineFit.so
The following transcript shows that this is necessary:
pax> g++ --soname=x -Wall -o qq qq.cpp
cc1plus: error: unrecognized command line option "-fsoname=x"
pax> g++ -Wl,-soname=x -Wall -o qq qq.cpp
pax>
From the online GNU docs for gcc:
-Wl,option: pass option as an option to the linker. If option contains commas, it is split into multiple options at the commas.
I know this is an old question but after a week of struggling I thought I should post my findings.
I've successfully edited the makefiles for this so they can compile on Ubuntu 12.04 x64.
You can remove the -soname option completely, it seemingly is unnecessary.
As mentioned: all "m32" change to "m64".
You can replace "$ROOTSYS/libs" with "$ROOTLIBS"
and with TwoPad makefile reorder the library order (under LIBS += (.....)) so that -lTwoPad is NOT last on the list, and for VisuSLitrani make -lPhysMore last in its group.
As far as I know the errors saying "set but not used" can be ignored.
If any of this still doesn't work contact me back and I can send you my makefiles.
Here a nice explanation of the -soname linker option, how to call it and what it is good for.
Summary
You can simply use gcc -shared -Wl,-soname,libfoo_v1.so -o libfoo_v1.so libfoo_v1.o and skip the following discussion ;)
call it as gcc -shared -Wl,-soname,libfoo.so -o libfoo_v1.so libfoo_v1.o
after compiling you need to create an symbolic link pointing to libfoo_v1.so ln -s libfoo_v1.so libfoo.so before you can execute your code.
This is used to link against different shared libraries during compiletime and runtime. Obviously these libraries need a similar interface. You can use this for managing different versions.
I'm learning Objective-C language. Since I don't have a Mac, I'm compiling and running my code within Ubuntu 11.04 platform.
Until now, I was using gcc to compile. I've installed GNUStep and all was working. But then I started to try some Objective-C 2.0 features, like #property and #synthesize, that gcc does not allow.
So I tried to compile the code with Clang, but it seems that it is not correctly linking my code with the GNUStep libraries, not even with a simple Hello world program.
For example, if I compile the following code:
#import <Foundation/Foundation.h>
int main(void) {
NSLog(#"Hello world!");
return 0;
}
The output of the compiler is:
/tmp/cc-dHZIp1.o: In function `main':
test.m:(.text+0x1f): undefined reference to `NSLog'
/tmp/cc-dHZIp1.o: In function `.objc_load_function':
test.m:(.text+0x3c): undefined reference to `__objc_exec_class'
collect2: ld returned 1 exit status
clang: error: linker (via gcc) command failed with exit code 1 (use -v to see invocation)
The command I'm using to compile is
clang -I /usr/include/GNUstep/ test.m -o test
with the -I directive to include the GNUStep libraries (otherwise, Clang is not able to find Foundation.h).
I've googled my problem, and visited both GNUStep and Clang web pages, but I haven't found a solution to it. So any help will be appreciated.
Thanks!
The problem was that the library gnustep-base was not being used by the linker. So the solution to this was using the option -Xlinker, that sends arguments to the linker used by clang:
clang -I /usr/include/GNUstep/ -Xlinker -lgnustep-base test.m -o test
The statement "-X linker -lgnustep-base" made the magic. However, I had problems with this command related to the class that represents a string in Objective-C:
./test: Uncaught exception NSInvalidArgumentException, reason: GSFFIInvocation:
Class 'NXConstantString'(instance) does not respond to forwardInvocation: for
'hasSuffix:'
I could solve it adding the argument "-fconstant-string-class=NSConstantString":
clang -I /usr/include/GNUstep/ -fconstant-string-class=NSConstantString \
-Xlinker -lgnustep-base test.m -o test
In addition, I've tried with some Objective-C 2.0 pieces of code and it seems to work.
Thank you for the help!
You can try gcc compiler:
First of all install GNU Objective-C Runtime: sudo apt-get install gobjc
then compile: gcc -o hello hello.m -Wall -lobjc
You are not able to use ObjC 2.0 features because you're missing a ObjC-runtime supporting those. GCC's runtime is old and outdated, it doesn't support ObjC 2.0. Clang/LLVM doesn't have a acompanied runtime, you need to install the ObjC2-runtime from GNUstep (which can be found here: https://github.com/gnustep/libobjc2 ) and reinstall GNUstep using this runtime.
Here are some bash scripts for different Ubuntu versions, that do everything for you:
http://wiki.gnustep.org/index.php/GNUstep_under_Ubuntu_Linux
And please don't try to reinvent GNUstep make, instead, use it:
http://www.gnustep.org/resources/documentation/Developer/Make/Manual/gnustep-make_1.html
If you really don't think so, here is some excerpt from there:
1.2 Structure of a Makefile
Here is an example makefile (named GNUmakefile to emphasis the fact that it relies on special features of the GNU make program).
#
# An example GNUmakefile
#
# Include the common variables defined by the Makefile Package
include $(GNUSTEP_MAKEFILES)/common.make
# Build a simple Objective-C program
TOOL_NAME = simple
# The Objective-C files to compile
simple_OBJC_FILES = simple.m
-include GNUmakefile.preamble
# Include in the rules for making GNUstep command-line programs
include $(GNUSTEP_MAKEFILES)/tool.make
-include GNUmakefile.postamble
This is all that is necessary to define the project.
In your case replace all occurrences of simple with test and you're done
1.3 Running Make
Normally to compile a package which uses the Makefile Package it is purely a matter of typing make from the top-level directory of the package, and the package is compiled without any additional interaction.
Assuming you have your .h and .m ready on a Linux server, which command would you issue to GCC to have it compiled?
The relevant parts:
gcc -c -Wno-import List.m
gcc -o prog -Wno-import List.o main.o -lobjc
. . . make sure that the Objective-C library and header files (objc/Object.h) were installed when gcc was built.
Note that when linking Objective-C with gcc, you need to specify the Objective-C library by using the -lobjc switch.
See this link for more information.
Additional link with possible solution to the missing compiler issue:
Try installing either gobjc++ or gobjc
sudo apt-get install gobjc++
gcc -x objective-c file.m -o out
Google is your friend
I am trying to compile CPP code on an Ubuntu machine. I read somewhere that g++ is included in gcc. so in CodeBlocks I included the GNU GCC compiler. Codeblocks returned an error saying that g++ was not found. Is g++ another seperate compiler?
g++ is for compiling C++, gcc is for compiling C. Two different compilers for two different languages!
I'm not very familiar with g++ but g++ is a C++ compiler and C++ is an extension of the C language so all C code can be compiled with a C++ compiler. So you could say that g++ contains a C compiler but saying that g++ contains gcc isn't correct I think.
Both g++ and gcc programs are from the same free software project, GCC. However, on Ubuntu you have several different packages for them, so install the g++-4.6 or the g++ package with gcc-4.6 or gcc one. (if you don't install both, you won't be able to compile both C & C++).
Both programs can compile C and C++ files, assuming the C files are suffixed with .c and the C++ ones with .cc or .cpp (etc..).
But they won't do exactly the same things, in particular, they won't link the same default libraries.
To understand what they do, you can run
gcc -v -Wall -g myprog.cc -o myprog
and
g++ -v -Wall -g myprog.cc -o myprog
and you'll see the differences. The -v flag often means "verbose".