Where do you see libstdc++11? The current in-development version of libstdc++ is 6.0.28 so I'm guessing libstdc++11 must be a package name specific to some distro.

Minimal step-by-step example

Compile GCC from source. Condensed commands:

sudo apt-get build-dep gcc
git clone git://gcc.gnu.org/git/gcc.git
cd gcc
git checkout gcc-6_4_0-release
./contrib/download_prerequisites
mkdir build
cd build
../configure --enable-languages=c,c++ --prefix="$(pwd)/install"
make -j`nproc`
make install

Wait from 30-minutes to two hours. Now let's use this test program a.cpp:

#include <cassert>
#include <queue>

int main() {
    std::priority_queue<int> q;
    q.emplace(2);
    q.emplace(1);
    q.emplace(3);
    assert(q.top() == 3);
    q.pop();
    assert(q.top() == 2);
    q.pop();
    assert(q.top() == 1);
    q.pop();
}

First compile and run it to ensure that the initial compilation worked:

gcc/build/install/bin/g++ -g -std=c++11 -O0 -o a.out ./a.cpp
./a.out

Now let's hack up the priority_queue constructor.

First, you can find the actual constructor easily with GDB as explained at: When should I use make_heap vs. Priority Queue?

So we hack it up with this patch:

diff --git a/libstdc++-v3/include/bits/stl_queue.h b/libstdc++-v3/include/bits/stl_queue.h
index 5d255e7300b..deec7bc4d99 100644
--- a/libstdc++-v3/include/bits/stl_queue.h
+++ b/libstdc++-v3/include/bits/stl_queue.h
@@ -61,6 +61,7 @@
 #if __cplusplus >= 201103L
 # include <bits/uses_allocator.h>
 #endif
+#include <iostream>
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -444,7 +445,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       priority_queue(const _Compare& __x = _Compare(),
             _Sequence&& __s = _Sequence())
       : c(std::move(__s)), comp(__x)
-      { std::make_heap(c.begin(), c.end(), comp); }
+      {
+        std::cout << "hacked" << std::endl;
+        std::make_heap(c.begin(), c.end(), comp);
+      }
 
       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
    explicit

Then rebuild and re-install just libstdc++ to save a lot of time:

cd gcc/build/x86_64-pc-linux-gnu/libstdc++-v3
make -j`nproc`
make install

and now the next build and run:

gcc/build/install/bin/g++ -g -std=c++11 -O0 -o a.out ./a.cpp
./a.out

outputs:

hacked

Tested on Ubuntu 16.04.

Ubuntu 22.04, GCC 12.1

We need to either:

• add --disable-multilib to ./configure
• (untested) sudo apt install gcc-multilib g++-multilib, these are linked to support for 32-bit executables: How to Compile 32-bit Apps on 64-bit Ubuntu?

or else it fails with:

configure: WARNING: using in-tree isl, disabling version check          
*** This configuration is not supported in the following subdirectories:                                                                                                                                           
     gnattools gotools target-libada target-libphobos target-zlib target-libbacktrace target-libgfortran target-libgo target-libffi target-libobjc target-liboffloadmic
    (Any other directories should still work fine.) 
checking for default BUILD_CONFIG... bootstrap-debug
checking for --enable-vtable-verify... no
/usr/bin/ld: cannot find Scrt1.o: No such file or directory
/usr/bin/ld: cannot find crti.o: No such file or directory
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/11/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc: No such file or directory
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/11/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc: No such file or directory
collect2: error: ld returned 1 exit status                                                               
configure: error: I suspect your system does not have 32-bit development libraries (libc and headers). If you have them, rerun configure with --enable-multilib. If you do not have them, and want to build a 64-bi
t-only compiler, rerun configure with --disable-multilib. 

glibc

As a bonus, if you are also interested in C: Multiple glibc libraries on a single host

Related:

• https://unix.stackexchange.com/questions/657370/how-to-compile-libstdc-with-specific-compiler-option

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++11 to 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.

Minimal step-by-step example

Compile GCC from source. Condensed commands:

sudo apt-get build-dep gcc
git clone git://gcc.gnu.org/git/gcc.git
cd gcc
git checkout gcc-6_4_0-release
./contrib/download_prerequisites
mkdir build
cd build
../configure --enable-languages=c,c++ --prefix="$(pwd)/install"
make -j`nproc`

Wait from 30-minutes to two hours. Now let's use this test program a.cpp:

#include <cassert>
#include <queue>

int main() {
    std::priority_queue<int> q;
    q.emplace(2);
    q.emplace(1);
    q.emplace(3);
    assert(q.top() == 3);
    q.pop();
    assert(q.top() == 2);
    q.pop();
    assert(q.top() == 1);
    q.pop();
}

First compile and run it to ensure that the initial compilation worked:

gcc/build/install/bin/g++ -g -std=c++11 -O0 -o a.out ./a.cpp
./a.out

Now let's hack up the priority_queue constructor.

First, you can find the actual constructor easily with GDB as explained at: https://stackoverflow.com/questions/11266360/when-should-i-use-make-heap-vs-priority-queue/51945521#51945521

So we hack it up with this patch:

diff --git a/libstdc++-v3/include/bits/stl_queue.h b/libstdc++-v3/include/bits/stl_queue.h
index 5d255e7300b..deec7bc4d99 100644
--- a/libstdc++-v3/include/bits/stl_queue.h
+++ b/libstdc++-v3/include/bits/stl_queue.h
@@ -61,6 +61,7 @@
 #if __cplusplus >= 201103L
 # include <bits/uses_allocator.h>
 #endif
+#include <iostream>
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
@@ -444,7 +445,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       priority_queue(const _Compare& __x = _Compare(),
             _Sequence&& __s = _Sequence())
       : c(std::move(__s)), comp(__x)
-      { std::make_heap(c.begin(), c.end(), comp); }
+      {
+        std::cout << "hacked" << std::endl;
+        std::make_heap(c.begin(), c.end(), comp);
+      }
 
       template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
    explicit

Then rebuild and re-install just libstdc++ to save a lot of time:

cd gcc/build/x86_64-pc-linux-gnu/libstdc++-v3
make -j`nproc`
make install

and now the next build and run:

gcc/build/install/bin/g++ -g -std=c++11 -O0 -o a.out ./a.cpp
./a.out

outputs:

hacked

Tested on Ubuntu 16.04.

glibc

As a bonus, if you are also interested in C: https://stackoverflow.com/questions/847179/multiple-glibc-libraries-on-a-single-host/52454603#52454603

Related:

• https://stackoverflow.com/questions/21872229/how-to-edit-and-re-build-the-gcc-libstdc-c-standard-library-source/51946224#51946224