The LIBRARY_PATH environment variable is pretty standard. It is known to majority of compilers.
You should also use C_INCLUDE_PATH and/or CPLUS_INCLUDE_PATH. These two a more gcc specific (other compilers prefer INCLUDE without language separation).
You can also ignore the environment variables completely and specify the correct libstdc++ directly in the command line.
g++ main.cpp /software/gcc10/.../libstdc++.a
c++ - How do you find what version of libstdc++ library is installed on your linux machine? - Stack Overflow
How can I know the libstdc++ version shipped with each gcc version? - Stack Overflow
libstdc++ vs libstdc++11 when using gcc version 8+ and -std=c++17
What is libstdc++11?
More on reddit.comgcc - What is libstdc++.so.6 and GLIBCXX_3.4.20? - Unix & Linux Stack Exchange
To find which library is being used you could run
Copy $ /sbin/ldconfig -p | grep stdc++
libstdc++.so.6 (libc6) => /usr/lib/libstdc++.so.6
The list of compatible versions for libstdc++ version 3.4.0 and above is provided by
Copy $ strings /usr/lib/libstdc++.so.6 | grep LIBCXX
GLIBCXX_3.4
GLIBCXX_3.4.1
GLIBCXX_3.4.2
...
For earlier versions the symbol GLIBCPP is defined.
The date stamp of the library is defined in a macro __GLIBCXX__ or __GLIBCPP__ depending on the version:
Copy// libdatestamp.cxx
#include <cstdio>
int main(int argc, char* argv[]){
#ifdef __GLIBCPP__
std::printf("GLIBCPP: %d\n",__GLIBCPP__);
#endif
#ifdef __GLIBCXX__
std::printf("GLIBCXX: %d\n",__GLIBCXX__);
#endif
return 0;
}
$ g++ libdatestamp.cxx -o libdatestamp
$ ./libdatestamp
GLIBCXX: 20101208
The table of datestamps of libstdc++ versions is listed in the documentation:
What exactly do you want to know?
The shared library soname? That's part of the filename, libstdc++.so.6, or shown by readelf -d /usr/lib64/libstdc++.so.6 | grep soname.
The minor revision number? You should be able to get that by simply checking what the symlink points to:
Copy$ ls -l /usr/lib/libstdc++.so.6
lrwxrwxrwx. 1 root root 19 Mar 23 09:43 /usr/lib/libstdc++.so.6 -> libstdc++.so.6.0.16
That tells you it's 6.0.16, which is the 16th revision of the libstdc++.so.6 version, which corresponds to the GLIBCXX_3.4.16 symbol versions.
Or do you mean the release it comes from? It's part of GCC so it's the same version as GCC, so unless you've screwed up your system by installing unmatched versions of g++ and libstdc++.so you can get that from:
Copy$ g++ -dumpversion
4.6.3
Or, on most distros, you can just ask the package manager. On my Fedora host that's
Copy$ rpm -q libstdc++
libstdc++-4.6.3-2.fc16.x86_64
libstdc++-4.6.3-2.fc16.i686
As other answers have said, you can map releases to library versions by checking the ABI docs
You look in the manual, specifically at http://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html which shows the library version numbers for each GCC release.
You can just check the GCC source code, for example the libstdc++/ChangeLog file that comes with it. It shouldn't be too hard to script that.
At first sight, libstdc++ isn't getting real version numbers anymore, they just use the source code repository revision id in the ChangeLog files.
Is there a difference between libstdc++ and libstdc++11 in the current releases of gcc (or at least gcc >=8)?
I want to create libraries that support code using the C++17 standard.
I can't find any concise answer on which lib to use or if it even matters.
On Linux: In general, all commonly available linux distributions will use libstdc++ by default, and all modern versions of GCC come with a libstdc++ that supports C++11. If you want to compile c++11 code here, use one of:
g++ -std=c++11 input.cxx -o a.out(usually GNU compiler)g++ -std=gnu++11 input.cxx -o a.out
On OS X before Mavericks: g++ was actually an alias for clang++ and Apple's old version of libstdc++ was the default. You could use libc++ (which included c++11 library support) by passing -stdlib=libc++. If you want to compile c++11 code here, use one of:
g++ -std=c++11 -stdlib=libc++ input.cxx -o a.out(clang, not GNU compiler!)g++ -std=gnu++11 -stdlib=libc++ input.cxx -o a.out(clang, not GNU compiler!)clang++ -std=c++11 -stdlib=libc++ input.cxx -o a.outclang++ -std=gnu++11 -stdlib=libc++ input.cxx -o a.out
On OS X since Mavericks: libc++ is the default and you should not pass any -stdlib=<...> flag. Since Xcode 10, building against libstdc++ is not supported at all anymore. Existing code built against libstdc++ will keep working because libstdc++.6.dylib is still provided, but compiling new code against libstdc++ is not supported.
clang++ -std=c++11 input.cxx -o a.outclang++ -std=gnu++11 input.cxx -o a.out
When is it necessary to use use the flag
-stdlib=libstdc++for the compiler and linker when compiling with gcc?
Short answer: never
Longer answer: -stdlib is a Clang flag and will not work with any version of GCC ever released. On macOS sometimes the gcc and g++ commands are actually aliases for Clang not GCC, and the version of libstdc++ that Apple ships is ancient (circa 2008) so of course it doesn't support C++11. This means that on macOS when using Clang-pretending-to-be-GCC, you can use -stdlib=libc++ to select Clang's new C++11-compatible library, or you can use -stdlib=libstdc++ to select the pre-C++11 antique version of libstdc++ that belongs in a museum. But on GNU/Linux gcc and g++ really are GCC not Clang, and so the -stdlib option won't work at all.
Edit: Since I wrote this answer, GCC was changed to conditionally support the -stdlib flag, but for most platforms that support is disabled by default. Even when it's enabled, the default is -stdlib=libstdc++ so you still never need to say that explicitly. GCC will still automatically use libstdc++.
Does the compiler automatically use libstdc++?
Yes, GCC always uses libstdc++ unless you tell it to use no standard library at all with the -nostdlib or -nostdlib++ option (in which case you either need to avoid using any standard library features, or use -I and -L and -l flags to point it to an alternative set of header and library files).
I am using gcc4.8.2 on Ubuntu 13.10 and I would like to use the c++11 standard. I already pass
-std=c++11to the compiler.
You don't need to do anything else. GCC comes with its own implementation of the C++ standard library (libstdc++) which is developed and tested alongside GCC itself so the version of GCC and the version of libstdc++ are 100% compatible. If you compile with -std=c++11 then that enables the C++11 features in g++ compiler and also the C++11 features in the libstdc++ headers.