The first generation GNU C++ library was called libg++. It was a +separate GNU project, although reliably paired with GCC. Rumors imply +that it had a working relationship with at least two kinds of +dinosaur. +
Some background: libg++ was designed and created when there was no
+ISO standard to provide guidance. Classes like linked lists are now
+provided for by list<T> and do not need to be
+created by genclass. (For that matter, templates exist
+now and are well-supported, whereas genclass (mostly) predates them.)
+
There are other classes in libg++ that are not specified in the +ISO Standard (e.g., statistical analysis). While there are a lot of +really useful things that are used by a lot of people, the Standards +Committee couldn't include everything, and so a lot of those +âobviousâ classes didn't get included. +
Known Issues include many of the limitations of its immediate ancestor.
Portability notes and known implementation limitations are as follows.
At least some older implementations don't have std::ios_base, so you should use std::ios::badbit, std::ios::failbit and std::ios::eofbit and std::ios::goodbit.
+
+ In earlier versions of the standard,
+ fstream.h,
+ ostream.h
+ and istream.h
+ used to define
+ cout, cin and so on. ISO C++ specifies that one needs to include
+ iostream
+ explicitly to get the required definitions.
+
Some include adjustment may be required.
This project is no longer maintained or supported, and the sources +archived. For the desperate, +the GCC extensions +page describes where to find the last libg++ source. The code is +considered replaced and rewritten. +
+ The second generation GNU C++ library was called libstdc++, or + libstdc++-v2. It spans the time between libg++ and pre-ISO C++ + standardization and is usually associated with the following GCC + releases: egcs 1.x, gcc 2.95, and gcc 2.96. +
+ The STL portions of this library are based on SGI/HP STL release 3.11. +
+ This project is no longer maintained or supported, and the sources + archived. The code is considered replaced and rewritten. +
+ Portability notes and known implementation limitations are as follows. +
+ Some care is required to support C++ compiler and or library
+ implementation that do not have the standard library in
+ namespace std.
+
+ The following sections list some possible solutions to support compilers
+ that cannot ignore std::-qualified names.
+
+ First, see if the compiler has a flag for this. Namespace
+ back-portability-issues are generally not a problem for g++
+ compilers that do not have libstdc++ in std::, as the
+ compilers use -fno-honor-std (ignore
+ std::, :: = std::) by default. That is,
+ the responsibility for enabling or disabling std:: is
+ on the user; the maintainer does not have to care about it. This
+ probably applies to some other compilers as well.
+
+ Second, experiment with a variety of pre-processor tricks. +
+ By defining std as a macro, fully-qualified namespace
+ calls become global. Volia.
+
+#ifdef WICKEDLY_OLD_COMPILER +# define std +#endif +
+ Thanks to Juergen Heinzl who posted this solution on gnu.gcc.help. +
+ Another pre-processor based approach is to define a macro
+ NAMESPACE_STD, which is defined to either
+ â â or âstdâ based on a compile-type
+ test. On GNU systems, this can be done with autotools by means of
+ an autoconf test (see below) for HAVE_NAMESPACE_STD,
+ then using that to set a value for the NAMESPACE_STD
+ macro. At that point, one is able to use
+ NAMESPACE_STD::string, which will evaluate to
+ std::string or ::string (i.e., in the
+ global namespace on systems that do not put string in
+ std::).
+
+dnl @synopsis AC_CXX_NAMESPACE_STD +dnl +dnl If the compiler supports namespace std, define +dnl HAVE_NAMESPACE_STD. +dnl +dnl @category Cxx +dnl @author Todd Veldhuizen +dnl @author Luc Maisonobe <luc@spaceroots.org> +dnl @version 2004-02-04 +dnl @license AllPermissive +AC_DEFUN([AC_CXX_NAMESPACE_STD], [ + AC_CACHE_CHECK(if g++ supports namespace std, + ac_cv_cxx_have_std_namespace, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([#include <iostream> + std::istream& is = std::cin;],, + ac_cv_cxx_have_std_namespace=yes, ac_cv_cxx_have_std_namespace=no) + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_have_std_namespace" = yes; then + AC_DEFINE(HAVE_NAMESPACE_STD,,[Define if g++ supports namespace std. ]) + fi +]) +
+ The following illustrate implementation-allowed illegal iterator + use, and then correct use. +
+ you cannot do ostream::operator<<(iterator)
+ to print the address of the iterator => use
+ operator<< &*iterator instead
+
+ you cannot clear an iterator's reference (iterator =
+ 0) => use iterator = iterator_type();
+
+ if (iterator) won't work any more => use
+ if (iterator != iterator_type())
+
+ Glibc 2.0.x and 2.1.x define ctype.h functionality as macros
+ (isspace, isalpha etc.).
+
+ This implementations of libstdc++, however, keep these functions + as macros, and so it is not back-portable to use fully qualified + names. For example: +
+#include <cctype>
+int main() { std::isspace('X'); }
++ Results in something like this: +
+std:: (__ctype_b[(int) ( ( 'X' ) )] & (unsigned short int) _ISspace ) ; +
+ A solution is to modify a header-file so that the compiler tells
+ ctype.h to define functions
+ instead of macros:
+
+// This keeps isalnum, et al from being propagated as macros. +#if __linux__ +# define __NO_CTYPE 1 +#endif +
+ Then, include ctype.h
+
+ Another problem arises if you put a using namespace
+ std; declaration at the top, and include ctype.h. This will result in
+ ambiguities between the definitions in the global namespace
+ (ctype.h) and the
+ definitions in namespace std::
+ (<cctype>).
+
+ One solution is to add an autoconf-test for this: +
+AC_MSG_CHECKING(for container::at)
+AC_TRY_COMPILE(
+[
+#include <vector>
+#include <deque>
+#include <string>
+
+using namespace std;
+],
+[
+deque<int> test_deque(3);
+test_deque.at(2);
+vector<int> test_vector(2);
+test_vector.at(1);
+string test_string(âtest_stringâ);
+test_string.at(3);
+],
+[AC_MSG_RESULT(yes)
+AC_DEFINE(HAVE_CONTAINER_AT)],
+[AC_MSG_RESULT(no)])
+
+ If you are using other (non-GNU) compilers it might be a good idea
+ to check for string::at separately.
+
+ Use some kind of autoconf test, plus this: +
+#ifdef HAVE_CHAR_TRAITS +#define CPP_EOF std::char_traits<char>::eof() +#else +#define CPP_EOF EOF +#endif +
+ There are two functions for deleting the contents of a string:
+ clear and erase (the latter returns the
+ string).
+
+void
+clear() { _M_mutate(0, this->size(), 0); }
+
+basic_string&
+erase(size_type __pos = 0, size_type __n = npos)
+{
+ return this->replace(_M_check(__pos), _M_fold(__pos, __n),
+ _M_data(), _M_data());
+}
+
+ Unfortunately, clear is not implemented in this
+ version, so you should use erase (which is probably
+ faster than operator=(charT*)).
+
+ These are no longer supported. Please use stringstreams instead. +
+ Although the ISO standard i/ostringstream-classes are
+ provided, (sstream), for
+ compatibility with older implementations the pre-ISO
+ i/ostrstream (strstream) interface is also provided,
+ with these caveats:
+
+ strstream is considered to be deprecated
+
+ strstream is limited to char
+
+ with ostringstream you don't have to take care of
+ terminating the string or freeing its memory
+
+ istringstream can be re-filled (clear();
+ str(input);)
+
+ You can then use output-stringstreams like this: +
+#ifdef HAVE_SSTREAM +# include <sstream> +#else +# include <strstream> +#endif + +#ifdef HAVE_SSTREAM + std::ostringstream oss; +#else + std::ostrstream oss; +#endif + +oss << âName=â << m_name << â, number=â << m_number << std::endl; +... +#ifndef HAVE_SSTREAM + oss << std::ends; // terminate the char*-string +#endif + +// str() returns char* for ostrstream and a string for ostringstream +// this also causes ostrstream to think that the buffer's memory +// is yours +m_label.set_text(oss.str()); +#ifndef HAVE_SSTREAM + // let the ostrstream take care of freeing the memory + oss.freeze(false); +#endif +
+ Input-stringstreams can be used similarly: +
+std::string input; +... +#ifdef HAVE_SSTREAM +std::istringstream iss(input); +#else +std::istrstream iss(input.c_str()); +#endif + +int i; +iss >> i; +
One (the only?) restriction is that an istrstream cannot be re-filled: +
+std::istringstream iss(numerator); +iss >> m_num; +// this is not possible with istrstream +iss.clear(); +iss.str(denominator); +iss >> m_den; +
+If you don't care about speed, you can put these conversions in + a template-function: +
+template <class X>
+void fromString(const string& input, X& any)
+{
+#ifdef HAVE_SSTREAM
+std::istringstream iss(input);
+#else
+std::istrstream iss(input.c_str());
+#endif
+X temp;
+iss >> temp;
+if (iss.fail())
+throw runtime_error(..)
+any = temp;
+}
++ Another example of using stringstreams is in this howto. +
There is additional information in the libstdc++-v2 info files, in +particular âinfo iostreamâ. +
+ Classes wstring and
+ char_traits<wchar_t> are
+ not supported.
+
+ Earlier GCC releases had a somewhat different approach to + threading configuration and proper compilation. Before GCC 3.0, + configuration of the threading model was dictated by compiler + command-line options and macros (both of which were somewhat + thread-implementation and port-specific). There were no + guarantees related to being able to link code compiled with one + set of options and macro setting with another set. +
+ For GCC 3.0, configuration of the threading model used with + libraries and user-code is performed when GCC is configured and + built using the --enable-threads and --disable-threads options. + The ABI is stable for symbol name-mangling and limited functional + compatibility exists between code compiled under different + threading models. +
+ The libstdc++ library has been designed so that it can be used in + multithreaded applications (with libstdc++-v2 this was only true + of the STL parts.) The first problem is finding a + fast method of implementation portable to + all platforms. Due to historical reasons, some of the library is + written against per-CPU-architecture spinlocks and other parts + against the gthr.h abstraction layer which is provided by gcc. A + minor problem that pops up every so often is different + interpretations of what "thread-safe" means for a + library (not a general program). We currently use the same + definition that SGI uses for their STL subset. However, + the exception for read-only containers only applies to the STL + components. This definition is widely-used and something similar + will be used in the next version of the C++ standard library. +
+ Here is a small link farm to threads (no pun) in the mail + archives that discuss the threading problem. Each link is to the + first relevant message in the thread; from there you can use + "Thread Next" to move down the thread. This farm is in + latest-to-oldest order. +
+ Our threading expert Loren gives a breakdown of the + six situations involving threads for the 3.0 + release series. +
+ + This message inspired a recent updating of issues with + threading and the SGI STL library. It also contains some + example POSIX-multithreaded STL code. +
+ (A large selection of links to older messages has been removed; + many of the messages from 1999 were lost in a disk crash, and the + few people with access to the backup tapes have been too swamped + with work to restore them. Many of the points have been + superseded anyhow.) +
The third generation GNU C++ library is called libstdc++, or +libstdc++-v3. +
The subset commonly known as the Standard Template Library + (chapters 23 through 25, mostly) is adapted from the final release + of the SGI STL (version 3.3), with extensive changes. +
A more formal description of the V3 goals can be found in the + official design document. +
Portability notes and known implementation limitations are as follows.
The pre-ISO C++ headers
+ (iostream.h, defalloc.h etc.) are
+ available, unlike previous libstdc++ versions, but inclusion
+ generates a warning that you are using deprecated headers.
+
This compatibility layer is constructed by including the
+ standard C++ headers, and injecting any items in
+ std:: into the global namespace.
+
For those of you new to ISO C++ (welcome, time travelers!), no, + that isn't a typo. Yes, the headers really have new names. + Marshall Cline's C++ FAQ Lite has a good explanation in item + [27.4]. +
Some include adjustment may be required. What follows is an
+autoconf test that defines PRE_STDCXX_HEADERS when they
+exist.
+# AC_HEADER_PRE_STDCXX +AC_DEFUN([AC_HEADER_PRE_STDCXX], [ + AC_CACHE_CHECK(for pre-ISO C++ include files, + ac_cv_cxx_pre_stdcxx, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -Wno-deprecated" + + # Omit defalloc.h, as compilation with newer compilers is problematic. + AC_TRY_COMPILE([ + #include <new.h> + #include <iterator.h> + #include <alloc.h> + #include <set.h> + #include <hashtable.h> + #include <hash_set.h> + #include <fstream.h> + #include <tempbuf.h> + #include <istream.h> + #include <bvector.h> + #include <stack.h> + #include <rope.h> + #include <complex.h> + #include <ostream.h> + #include <heap.h> + #include <iostream.h> + #include <function.h> + #include <multimap.h> + #include <pair.h> + #include <stream.h> + #include <iomanip.h> + #include <slist.h> + #include <tree.h> + #include <vector.h> + #include <deque.h> + #include <multiset.h> + #include <list.h> + #include <map.h> + #include <algobase.h> + #include <hash_map.h> + #include <algo.h> + #include <queue.h> + #include <streambuf.h> + ],, + ac_cv_cxx_pre_stdcxx=yes, ac_cv_cxx_pre_stdcxx=no) + CXXFLAGS="$ac_save_CXXFLAGS" + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_pre_stdcxx" = yes; then + AC_DEFINE(PRE_STDCXX_HEADERS,,[Define if pre-ISO C++ header files are present. ]) + fi +]) +
Porting between pre-ISO headers and ISO headers is simple: headers
+like vector.h can be replaced with vector and a using
+directive using namespace std; can be put at the global
+scope. This should be enough to get this code compiling, assuming the
+other usage is correct.
+
At this time most of the features of the SGI STL extension have been + replaced by standardized libraries. + In particular, the unordered_map and unordered_set containers of TR1 + are suitable replacement for the non-standard hash_map and hash_set + containers in the SGI STL. +
Header files hash_map and hash_set moved
+to ext/hash_map and ext/hash_set,
+respectively. At the same time, all types in these files are enclosed
+in namespace __gnu_cxx. Later versions move deprecate
+these files, and suggest using TR1's unordered_map
+and unordered_set instead.
+
The extensions are no longer in the global or std
+ namespaces, instead they are declared in the __gnu_cxx
+ namespace. For maximum portability, consider defining a namespace
+ alias to use to talk about extensions, e.g.:
+
+ #ifdef __GNUC__
+ #if __GNUC__ < 3
+ #include <hash_map.h>
+ namespace extension { using ::hash_map; }; // inherit globals
+ #else
+ #include <backward/hash_map>
+ #if __GNUC__ == 3 && __GNUC_MINOR__ == 0
+ namespace extension = std; // GCC 3.0
+ #else
+ namespace extension = ::__gnu_cxx; // GCC 3.1 and later
+ #endif
+ #endif
+ #else // ... there are other compilers, right?
+ namespace extension = std;
+ #endif
+
+ extension::hash_map<int,int> my_map;
+ This is a bit cleaner than defining typedefs for all the + instantiations you might need. +
The following autoconf tests check for working HP/SGI hash containers. +
+# AC_HEADER_EXT_HASH_MAP +AC_DEFUN([AC_HEADER_EXT_HASH_MAP], [ + AC_CACHE_CHECK(for ext/hash_map, + ac_cv_cxx_ext_hash_map, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -Werror" + AC_TRY_COMPILE([#include <ext/hash_map>], [using __gnu_cxx::hash_map;], + ac_cv_cxx_ext_hash_map=yes, ac_cv_cxx_ext_hash_map=no) + CXXFLAGS="$ac_save_CXXFLAGS" + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_ext_hash_map" = yes; then + AC_DEFINE(HAVE_EXT_HASH_MAP,,[Define if ext/hash_map is present. ]) + fi +]) +
+# AC_HEADER_EXT_HASH_SET +AC_DEFUN([AC_HEADER_EXT_HASH_SET], [ + AC_CACHE_CHECK(for ext/hash_set, + ac_cv_cxx_ext_hash_set, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -Werror" + AC_TRY_COMPILE([#include <ext/hash_set>], [using __gnu_cxx::hash_set;], + ac_cv_cxx_ext_hash_set=yes, ac_cv_cxx_ext_hash_set=no) + CXXFLAGS="$ac_save_CXXFLAGS" + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_ext_hash_set" = yes; then + AC_DEFINE(HAVE_EXT_HASH_SET,,[Define if ext/hash_set is present. ]) + fi +]) +
The existence of ios::nocreate being used for
+input-streams has been confirmed, most probably because the author
+thought it would be more correct to specify nocreate explicitly. So
+it can be left out for input-streams.
+
For output streams, ânocreateâ is probably the default,
+unless you specify std::ios::trunc ? To be safe, you can
+open the file for reading, check if it has been opened, and then
+decide whether you want to create/replace or not. To my knowledge,
+even older implementations support app, ate
+and trunc (except for app ?).
+
+ Phil Edwards writes: It was considered and rejected for the ISO + standard. Not all environments use file descriptors. Of those + that do, not all of them use integers to represent them. +
+ For a portable solution (among systems which use
+ file descriptors), you need to implement a subclass of
+ std::streambuf (or
+ std::basic_streambuf<..>) which opens a file
+ given a descriptor, and then pass an instance of this to the
+ stream-constructor.
+
+ An extension is available that implements this.
+ ext/stdio_filebuf.h contains a derived class called
+ __gnu_cxx::stdio_filebuf.
+ This class can be constructed from a C FILE* or a file
+ descriptor, and provides the fd() function.
+
+ For another example of this, refer to + fdstream example + by Nicolai Josuttis. +
Check for complete library coverage of the C++1998/2003 standard. +
+# AC_HEADER_STDCXX_98 +AC_DEFUN([AC_HEADER_STDCXX_98], [ + AC_CACHE_CHECK(for ISO C++ 98 include files, + ac_cv_cxx_stdcxx_98, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([ + #include <cassert> + #include <cctype> + #include <cerrno> + #include <cfloat> + #include <ciso646> + #include <climits> + #include <clocale> + #include <cmath> + #include <csetjmp> + #include <csignal> + #include <cstdarg> + #include <cstddef> + #include <cstdio> + #include <cstdlib> + #include <cstring> + #include <ctime> + + #include <algorithm> + #include <bitset> + #include <complex> + #include <deque> + #include <exception> + #include <fstream> + #include <functional> + #include <iomanip> + #include <ios> + #include <iosfwd> + #include <iostream> + #include <istream> + #include <iterator> + #include <limits> + #include <list> + #include <locale> + #include <map> + #include <memory> + #include <new> + #include <numeric> + #include <ostream> + #include <queue> + #include <set> + #include <sstream> + #include <stack> + #include <stdexcept> + #include <streambuf> + #include <string> + #include <typeinfo> + #include <utility> + #include <valarray> + #include <vector> + ],, + ac_cv_cxx_stdcxx_98=yes, ac_cv_cxx_stdcxx_98=no) + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_stdcxx_98" = yes; then + AC_DEFINE(STDCXX_98_HEADERS,,[Define if ISO C++ 1998 header files are present. ]) + fi +]) +
Check for library coverage of the TR1 standard. +
+# AC_HEADER_STDCXX_TR1 +AC_DEFUN([AC_HEADER_STDCXX_TR1], [ + AC_CACHE_CHECK(for ISO C++ TR1 include files, + ac_cv_cxx_stdcxx_tr1, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([ + #include <tr1/array> + #include <tr1/ccomplex> + #include <tr1/cctype> + #include <tr1/cfenv> + #include <tr1/cfloat> + #include <tr1/cinttypes> + #include <tr1/climits> + #include <tr1/cmath> + #include <tr1/complex> + #include <tr1/cstdarg> + #include <tr1/cstdbool> + #include <tr1/cstdint> + #include <tr1/cstdio> + #include <tr1/cstdlib> + #include <tr1/ctgmath> + #include <tr1/ctime> + #include <tr1/cwchar> + #include <tr1/cwctype> + #include <tr1/functional> + #include <tr1/memory> + #include <tr1/random> + #include <tr1/regex> + #include <tr1/tuple> + #include <tr1/type_traits> + #include <tr1/unordered_set> + #include <tr1/unordered_map> + #include <tr1/utility> + ],, + ac_cv_cxx_stdcxx_tr1=yes, ac_cv_cxx_stdcxx_tr1=no) + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_stdcxx_tr1" = yes; then + AC_DEFINE(STDCXX_TR1_HEADERS,,[Define if ISO C++ TR1 header files are present. ]) + fi +]) +
An alternative is to check just for specific TR1 includes, such as <unordered_map> and <unordered_set>. +
+# AC_HEADER_TR1_UNORDERED_MAP +AC_DEFUN([AC_HEADER_TR1_UNORDERED_MAP], [ + AC_CACHE_CHECK(for tr1/unordered_map, + ac_cv_cxx_tr1_unordered_map, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([#include <tr1/unordered_map>], [using std::tr1::unordered_map;], + ac_cv_cxx_tr1_unordered_map=yes, ac_cv_cxx_tr1_unordered_map=no) + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_tr1_unordered_map" = yes; then + AC_DEFINE(HAVE_TR1_UNORDERED_MAP,,[Define if tr1/unordered_map is present. ]) + fi +]) +
+# AC_HEADER_TR1_UNORDERED_SET +AC_DEFUN([AC_HEADER_TR1_UNORDERED_SET], [ + AC_CACHE_CHECK(for tr1/unordered_set, + ac_cv_cxx_tr1_unordered_set, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([#include <tr1/unordered_set>], [using std::tr1::unordered_set;], + ac_cv_cxx_tr1_unordered_set=yes, ac_cv_cxx_tr1_unordered_set=no) + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_tr1_unordered_set" = yes; then + AC_DEFINE(HAVE_TR1_UNORDERED_SET,,[Define if tr1/unordered_set is present. ]) + fi +]) +
Check for baseline language coverage in the compiler for the C++0xstandard. +
+# AC_COMPILE_STDCXX_OX
+AC_DEFUN([AC_COMPILE_STDCXX_0X], [
+ AC_CACHE_CHECK(if g++ supports C++0x features without additional flags,
+ ac_cv_cxx_compile_cxx0x_native,
+ [AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ AC_TRY_COMPILE([
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ typedef check<check<bool>> right_angle_brackets;
+
+ int a;
+ decltype(a) b;
+
+ typedef check<int> check_type;
+ check_type c;
+ check_type&& cr = c;],,
+ ac_cv_cxx_compile_cxx0x_native=yes, ac_cv_cxx_compile_cxx0x_native=no)
+ AC_LANG_RESTORE
+ ])
+
+ AC_CACHE_CHECK(if g++ supports C++0x features with -std=c++0x,
+ ac_cv_cxx_compile_cxx0x_cxx,
+ [AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ ac_save_CXXFLAGS="$CXXFLAGS"
+ CXXFLAGS="$CXXFLAGS -std=c++0x"
+ AC_TRY_COMPILE([
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ typedef check<check<bool>> right_angle_brackets;
+
+ int a;
+ decltype(a) b;
+
+ typedef check<int> check_type;
+ check_type c;
+ check_type&& cr = c;],,
+ ac_cv_cxx_compile_cxx0x_cxx=yes, ac_cv_cxx_compile_cxx0x_cxx=no)
+ CXXFLAGS="$ac_save_CXXFLAGS"
+ AC_LANG_RESTORE
+ ])
+
+ AC_CACHE_CHECK(if g++ supports C++0x features with -std=gnu++0x,
+ ac_cv_cxx_compile_cxx0x_gxx,
+ [AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ ac_save_CXXFLAGS="$CXXFLAGS"
+ CXXFLAGS="$CXXFLAGS -std=gnu++0x"
+ AC_TRY_COMPILE([
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ typedef check<check<bool>> right_angle_brackets;
+
+ int a;
+ decltype(a) b;
+
+ typedef check<int> check_type;
+ check_type c;
+ check_type&& cr = c;],,
+ ac_cv_cxx_compile_cxx0x_gxx=yes, ac_cv_cxx_compile_cxx0x_gxx=no)
+ CXXFLAGS="$ac_save_CXXFLAGS"
+ AC_LANG_RESTORE
+ ])
+
+ if test "$ac_cv_cxx_compile_cxx0x_native" = yes ||
+ test "$ac_cv_cxx_compile_cxx0x_cxx" = yes ||
+ test "$ac_cv_cxx_compile_cxx0x_gxx" = yes; then
+ AC_DEFINE(HAVE_STDCXX_0X,,[Define if g++ supports C++0x features. ])
+ fi
+])
+Check for library coverage of the C++0xstandard. +
+# AC_HEADER_STDCXX_0X +AC_DEFUN([AC_HEADER_STDCXX_0X], [ + AC_CACHE_CHECK(for ISO C++ 0x include files, + ac_cv_cxx_stdcxx_0x, + [AC_REQUIRE([AC_COMPILE_STDCXX_0X]) + AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -std=gnu++0x" + + AC_TRY_COMPILE([ + #include <cassert> + #include <ccomplex> + #include <cctype> + #include <cerrno> + #include <cfenv> + #include <cfloat> + #include <cinttypes> + #include <ciso646> + #include <climits> + #include <clocale> + #include <cmath> + #include <csetjmp> + #include <csignal> + #include <cstdarg> + #include <cstdbool> + #include <cstddef> + #include <cstdint> + #include <cstdio> + #include <cstdlib> + #include <cstring> + #include <ctgmath> + #include <ctime> + #include <cwchar> + #include <cwctype> + + #include <algorithm> + #include <array> + #include <bitset> + #include <complex> + #include <deque> + #include <exception> + #include <fstream> + #include <functional> + #include <iomanip> + #include <ios> + #include <iosfwd> + #include <iostream> + #include <istream> + #include <iterator> + #include <limits> + #include <list> + #include <locale> + #include <map> + #include <memory> + #include <new> + #include <numeric> + #include <ostream> + #include <queue> + #include <random> + #include <regex> + #include <set> + #include <sstream> + #include <stack> + #include <stdexcept> + #include <streambuf> + #include <string> + #include <tuple> + #include <typeinfo> + #include <type_traits> + #include <unordered_map> + #include <unordered_set> + #include <utility> + #include <valarray> + #include <vector> + ],, + ac_cv_cxx_stdcxx_0x=yes, ac_cv_cxx_stdcxx_0x=no) + AC_LANG_RESTORE + CXXFLAGS="$ac_save_CXXFLAGS" + ]) + if test "$ac_cv_cxx_stdcxx_0x" = yes; then + AC_DEFINE(STDCXX_0X_HEADERS,,[Define if ISO C++ 0x header files are present. ]) + fi +]) +
As is the case for TR1 support, these autoconf macros can be made for a finer-grained, per-header-file check. For <unordered_map> +
+# AC_HEADER_UNORDERED_MAP +AC_DEFUN([AC_HEADER_UNORDERED_MAP], [ + AC_CACHE_CHECK(for unordered_map, + ac_cv_cxx_unordered_map, + [AC_REQUIRE([AC_COMPILE_STDCXX_0X]) + AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -std=gnu++0x" + AC_TRY_COMPILE([#include <unordered_map>], [using std::unordered_map;], + ac_cv_cxx_unordered_map=yes, ac_cv_cxx_unordered_map=no) + CXXFLAGS="$ac_save_CXXFLAGS" + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_unordered_map" = yes; then + AC_DEFINE(HAVE_UNORDERED_MAP,,[Define if unordered_map is present. ]) + fi +]) +
+# AC_HEADER_UNORDERED_SET +AC_DEFUN([AC_HEADER_UNORDERED_SET], [ + AC_CACHE_CHECK(for unordered_set, + ac_cv_cxx_unordered_set, + [AC_REQUIRE([AC_COMPILE_STDCXX_0X]) + AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -std=gnu++0x" + AC_TRY_COMPILE([#include <unordered_set>], [using std::unordered_set;], + ac_cv_cxx_unordered_set=yes, ac_cv_cxx_unordered_set=no) + CXXFLAGS="$ac_save_CXXFLAGS" + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_unordered_set" = yes; then + AC_DEFINE(HAVE_UNORDERED_SET,,[Define if unordered_set is present. ]) + fi +]) +