I've just compiled GCC 4.7 to work with stdatomic.h, but I can't seem to -I it. stdatomic.h seems to live in /usr/include/c++/4.4.3, but then the linker tells me it needs a bunch of other files in dirs nearby. If I -I all of them, I still get the error undefined reference to atomic_flag_clear_explicit. Any ideas how I'm supposed to link this right?
First, if you are compiling with GCC 4.7 you should not be including or linking anything from a directory from GCC 4.4.
Second, -I only affects the search path for header files. "undefined reference" is a linker error and usually means it hasn't found the right library. You change the library search path with -L. The linker didn't say it didn't find a library with the right name, it says it didn't find a symbol, so clearly the library it did find didn't have that symbol. I'd suggest you have a versioning problem, perhaps caused by a installation problem.
The <stdatomic.h> header in GCC 4.4 and 4.5 was from an early draft of C++0x atomics, but is not part of the final standard, so it was removed from libstdc++.
The C++ compiler supports C++11 atomics via the C++11 <atomic> header, so you should use that header in C++ code.
When the C compiler supports C11 atomics, the <stdatomic.h> header will be provided again.
Using this command solved the problem for me:
$ scl enable devtoolset-7 bash
I got the same error as you when entering sudo make altinstall for installing Python 3.8.5 on CentOS 7.
Related
I want to cross compile my c++ program for an arm beaglebone. Compilation and linking works, but the binary is linked to the wrong version of libstdc++ and execution fails with
/usr/lib/arm-linux-gnueabihf/libstdc++.so.6: version `GLIBCXX_3.4.21' not found
On my host I have:
strings /usr/lib/gcc-cross/arm-linux-gnueabihf/5/libstdc++.so | grep GLIBCXX_3
...
GLIBCXX_3.4.20
GLIBCXX_3.4.21
An image of the beaglebone is mounted on ~/bbsysroot:
strings ~/bbsysroot/usr/lib/arm-linux-gnueabihf/libstdc++.so.6 | grep GLIBCXX_3
...
GLIBCXX_3.4.20
So, clearly, there is a version mismatch. That version mismatch is hard to avoid, since the host system is a different distribution.
The compilation command starts with
/usr/bin/arm-linux-gnueabihf-g++ -mfloat-abi=hard --sysroot=/home/user/bbsysroot
so I'm supplying the sysroot of the beaglebone to the compiler. I want that it looks for the libs in there and only in there. But
/usr/bin/arm-linux-gnueabihf-g++ --sysroot=/home/user/bbsysroot -print-search-dirs | grep libraries | sed 's/:/\n/g'
libraries
=/usr/lib/gcc-cross/arm-linux-gnueabihf/5/
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/arm-linux-gnueabihf/5/
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/arm-linux-gnueabihf/
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/../lib/
/home/user/bbsysroot/lib/arm-linux-gnueabihf/5/
/home/user/bbsysroot/lib/arm-linux-gnueabihf/
/home/user/bbsysroot/lib/../lib/
/home/user/bbsysroot/usr/lib/arm-linux-gnueabihf/5/
/home/user/bbsysroot/usr/lib/arm-linux-gnueabihf/
/home/user/bbsysroot/usr/lib/../lib/
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/
/home/user/bbsysroot/lib/
/home/user/bbsysroot/usr/lib/
shows, that it also looks on the host. I presume, that the host libraries have a higher priority and hence the wrong version is taken.
Is it possible to force the cross compiler to use the libraries from sysroot only? Or is that utterly wrong for some reason?
I got an answer, which might solve the problem, but i've moved on to another project since and can't test it. Though it might help others:
libstdc++ and also libgcc are actually part of the compiler and I think
that the best solution is:
use compiler version used by the BBB system (or earlier version)
upgrade those libraries on the BBB system
use '-static-libstdc++' option
You can try to use never compiler with older libgcc and libstdc++,
but I think that gcc may reference some newer functions. g++
also links libgcc dynamically by default.
I have downloaded Bellhop, which is an underwater acoustic simulator written in Fortran. It can be found here with the Makefile.
Question 1: I would like to know if it is possible to compile Fortran code, including everything needed, so a user without gfortran installed, can run it.
I have read here the following:
static linking
This section does not apply to Windows users, except for Cygwin users with gcc4-4.3.2-2 or later.
gfortran is composed of two main parts: the compiler, which creates the executable program from your code, and the library, which is used when you run your program afterwards. That explains why, if gfortran is installed in a non-standard directory, it may compile your code fine but the executable may fail with an error message like library not found. One way to avoid this (more ideas can be found on the binaries page) is to use the so-called "static linking", available with option -static gfortran then put the library code inside the program created, thus enabling it to run without the library present (like, on a computer where gfortran is not installed). Complete example is:
gfortran -static myfile.f -o program.exe
Reading this, I suppose that it is possible to do what I'm asking but I'm not very familiarized with fortran and makefiles. I don't understand this:
put the library code inside the program created
Question 2: How can I put the library code inside the program? Where can I find the library? What does "inside the program" means?
I'm running OSX 10.9.4 and gfortran
I solved my problem about compiling Fortran code with gfortran using static libraries.
As #M.S.B. said, using static-libgfortran worked for me under MacOS.
If somebody is having issues with linking the libquadmath.0.dylb library, remove libquadmath.0.dylib and libquadmath.dylib from /usr/local/gfortran/lib/
This doest the trick. Further information can be found here
I think the meaning of the bold part is actually
gfortran then puts the library code inside the
program created
That means using -static should be enough, there is no additional step. Just be advised you will need a static version of all the libraries that you link with.
I know this is very old tracker, but maybe somebody will be still interested in the solution that works.
Let's say we have code:
! fort_sample.f90
program main
write (*,*) 'Hello'
stop
end
First, compile the stuff:
gfortran -c -o fort_sample.o fort_sample.f90
Then, link stuff
ld -o ./fort_sample -no_compact_unwind \
-arch x86_64 -macosx_version_min 10.12.0 \
-lSystem \
/usr/local/gfortran/lib/libgfortran.a \
/usr/local/gfortran/lib/libquadmath.a \
/usr/local/gfortran/lib/gcc/x86_64-apple-darwin16/6.3.0/libgcc.a \
fort_sample.o
You can execute it
./fort_sample
Hello
You can notice that quadmath is no longer there
> otool -L fort_sample
fort_sample:
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.51.1)
I guess this is what you were looking for in a first place. No removing dylibs, no symbolic links, etc.
The current version of the option is -static-libgfortran. This means that the Fortran specific libraries of gfortran will be included into the executable. These are libraries are automatically found for a good installation of gfortran. This should produce an executable that should run on other computers with the same OS, even if that computer doesn't have gfortran installed. This option likely doesn't statically link all libraries, so there is some risk that some other shared library used on your computer won't be available on the other computer.
So after searching the web for a while, Ive decided to try here as it seems to be a good forum for discussion. Im trying to create a simple gcc plugin. The program code is attached in the end of this mail, but in plain english it registers the plugin and makes sure that the pragma_init function is called when pragmas are registered. It is here that I use c_register_pragma to intercept some of the pragmas.
I compile it using the example in http://gcc.gnu.org/onlinedocs/gccint/Plugins-building.html#Plugins-building. The compilation and linking works fine. However, when I load the plug-in I get:
gcc -c -fplugin=plugin.so test.c -o test.o
cc1: error: cannot load plugin plugin.so
plugin.so: undefined symbol: warning
What am I doing wrong? In addition, when including some header files (that will be required later), I get a lot of errors. For example, including "tree.h" yields (amongst 50 other errors):
/machmode.h:262:1: error: unknown type name 'class'
class bit_field_mode_iterator
^
/machmode.h:263:1: error: expected '=', ',', ';', 'asm' or '__attribute__' before '{' token
{
^
/plugin/include/tree.h:27:0,
from conftest.c:63:
/vec.h:220:8: error: field 'register_overhead' declared as a function
Anyone have a clue on what I am doing wrong?
Thank you
There are two problems here :
The error : "cannot load plugin plugin.so" means that you should add to your LD_LIBRARY_PATH the directory where you store your new shared library plugin.
The hundreds of errors you got with all the files in the include are resolved in my computer if you compile with g++ instead of gcc (not sure to understand why thought)
Which version of GCC are you using, both to compile your plugin, and to use the plugin? Run simply
gcc -v
without any other program argument to find out!
Did you install the appropriate package for GCC plugin development (on Debian or Ubuntu, it might be gcc-4.7-plugin-dev, but adapt the 4.7 version to your particular version of GCC)?
Did you install all the dependencies needed to build your GCC (on Debian or Ubuntu, apt-get build-dep gcc-4.7 gcc-4.7-plugin-dev)?
Recent versions of GCC (notably many GCC 4.7 shipped by distributions, and all GCC 4.8) are compiled by a C++ compiler, not a C compiler.
You may check how was your GCC built (in C or in C++) by running
nm -D -C $(gcc -print-file-name=cc1)
If that command shows typed C++ manged names, e.g. execute_ipa_pass_list(opt_pass*) instead of just execute_ipa_pass_list your GCC has been compiled with a C++ compiler (probably g++)
So you may need to use g++ (not gcc) to compile your GCC plugin.
As I commented, did you consider using MELT (a domain specific language to extend GCC) to extend or customize your gcc compiler?
I suggest downloading the very latest http://gcc-melt.org/melt-plugin-snapshot.tar.bz2 since I will release the next MELT in a few weeks for GCC 4.7 and 4.8
And don't expect to change the parsing behavior of your GCC with a plugin. That is not really possible (GCC provides only plugin hooks to add your builtins and pragmas, not to extend the parsed syntax).
my custom built gcc 4.6.0, installed in my home directory, on ubuntu 10.04, links the system libstdc++ instead of the custom built one, most of the time (as evidenced by ldd). to be more puzzling, using this newly built gcc, custom compiled openmpi libraries are linked correctly, and this is the only software i have compiled that behaves ok. does anybody have any explanation for this, or a workaround?
thanks
Isn't there an option to statically link the libstdc into the gcc when you configure it? --disable-shared if I understand how it works correctly. Worst case make another compile of gcc with that switch and see if you run into the issue.
I don't know why this isn't detailed more clearly on the GCC website for end-users. The GCC FAQ clearly states this is a common problem wrt libstdc++. Environment variables are troublesome. Wrapping the linker, nobody knows how to do that. Editing /etc/ld.so.conf isn't an option. Adding -Wl,-rpath everywhere, come on. The easiest solution is the specs file. For a typical 64-bit x86 Linux system, go into your custom gcc installation, in dirname `g++ -print-libgcc-file-name`and then run g++ -dumpspecs > specs. Edit that file, find the *link_command: section. After %(link_libgcc) add -rpath /home/user/bin/gcc-9/lib64 (of course use your own path). Or add the same rpath to end of *link: section. Alternatively, configure gcc with --with-specs='%{!static:%x{-rpath=/home/user/bin/gcc9/lib64} %x{-enable-new-dtags}}' . Enjoy your own C++ compiler that generates binaries that just work.
See also:
GCC specs file: how to get the installation path
Linking g++ 4.8 to libstdc++
How to configure libstdc++ with GCC 4.8?
I have build a g++ v4.4 from source by using the archives provided by gcc.gnu.org.
But the resulting g++ cannot compile some of our projects c++ files. I am receiving a message simply saying: assembler error. It turned out that the assembler chokes on some extremely long symbol names, e.g. symbols names with a length of more then 2k.
Am I missing something to get it to work?
I would very appreciate an advice on how to get this working!
Environment: Debian-Lenny 64bit
EDIT: The mentioned c++ files are compiling fine with g++ versions v4.2 and v4.3. So I don't think it is a bug in the assembler (from binutils v2.18). Just to be sure I have also tried with binutils v2.20 - but I got the identical error message.
EDIT: I need g++ v4.4.x for the purpose of comparing the output of different g++ versions (and there is no g++ v4.4 in the official lenny repositories)
If your analysis is correct, it seems the proper course of action would be to file a bug for binutils. Or gcc, if it turns out the long symbol names are due to a bug in gcc's name mangling.
Of course, a (preferably reduced) testcase will help the developers fix your problem. Heck, it could have helped SO readers to verify your problems.
You're going to have to compile the corresponding gas instead of depending on what lenny has in his refrigerator (/usr/bin).
Why don't a) upgrade or b) use the backports archive or c) rebuild from current Debian sources on your box? I happily run testing with g++ 4.2, 4.3 and 4.4.
Worst case, you could install a new Debian release in a virtual environment such as a chroot, a Xen or Kvm instance, or inside VirtualBox.