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diff --git a/libstdc++-v3/doc/html/17_intro/backwards_compatibility.html b/libstdc++-v3/doc/html/17_intro/backwards_compatibility.html new file mode 100644 index 00000000000..c9af980f0fc --- /dev/null +++ b/libstdc++-v3/doc/html/17_intro/backwards_compatibility.html @@ -0,0 +1,1073 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> + <meta name="AUTHOR" content="bkoz@gcc.gnu.org (Benjamin Kosnik), Felix Natter" /> + <meta name="KEYWORDS" content="C++, libstdc++, API, backward, compatibility" /> + <meta name="DESCRIPTION" content="Backwards Compatibility" /> + <meta name="GENERATOR" content="emacs and ten fingers" /> + <title>Backwards Compatibility</title> +<link rel="StyleSheet" href="lib3styles.css" type="text/css" /> +<link rel="Start" href="documentation.html" type="text/html" + title="GNU C++ Standard Library" /> +<link rel="Copyright" href="17_intro/license.html" type="text/html" /> +</head> +<body> + +<h1 class="centered"><a name="top">Backwards Compatibility</a></h1> + +<p class="fineprint"><em> + The latest version of this document is always available at + <a href="http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/backwards_compatibility.html"> + http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/backwards_compatibility.html</a>. +</em></p> + +<p><em> + To the <a href="http://gcc.gnu.org/libstdc++/">libstdc++ homepage</a>. +</em></p> + +<!-- ####################################################### --> +<hr /> +<h3 class="left"> + <a name="v1">First.</a> +</h3> + +<p> 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. +</p> + +<p>Known Issues include many of the limitations of its immediate ancestor.</p> + +<p>Portability notes and known implementation limitations are as follows.</p> + +<h5>No <code>ios_base</code></h5> + +<p> At least some older implementations don't have <code>std::ios_base</code>, so you should use <code>std::ios::badbit</code>, <code>std::ios::failbit</code> and <code>std::ios::eofbit</code> and <code>std::ios::goodbit</code>. +</p> + +<h5>No <code>cout</code> in <code>ostream.h</code>, no <code>cin</code> in <code>istream.h</code></h5> + +<p> + In earlier versions of the standard, + <tt><fstream.h></tt>, + <tt><ostream.h></tt> + and <tt><istream.h></tt> + used to define + <code>cout</code>, <code>cin</code> and so on. ISO C++ specifies that one needs to include + <tt><iostream></tt> + explicitly to get the required definitions. + </p> +<p> Some include adjustment may be required.</p> + + +<p>This project is no longer maintained or supported, and the sources +archived. The code is considered replaced and rewritten. +</p> + +<hr /> +<h3 class="left"> + <a name="v2">Second.</a> +</h3> +<p> 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. +</p> + +<p> The STL portions of this library are based on SGI/HP STL release 3.11. +</p> + +<p>Portability notes and known implementation limitations are as follows.</p> + +<h5>Namespace <code>std::</code> not supported</h5> + +<p> + Some care is required to support C++ compiler and or library + implementation that do not have the standard library in + <code>namespace std</code>. + </p> +<p> + The following sections list some possible solutions to support compilers + that cannot ignore <code>std::</code>-qualified names. + </p> + +<p> 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 <code>std::</code>, as + the compilers use <code>-fno-honor-std</code> (ignore + <code>std::</code>, <code>:: = std::</code>) by default. That + is, the responsibility for enabling or disabling + <code>std::</code> is on the user; the maintainer does not have + to care about it. This probably applies to some other compilers + as well. + </p> + +<p>Second, experiment with a variety of pre-processor tricks.</p> + +<p> By defining <code>std</code> as a macro, fully-qualified namespace calls become global. Volia. </p> + +<pre> +#ifdef WICKEDLY_OLD_COMPILER +# define std +#endif +</pre> +(thanks to Juergen Heinzl who posted this solution on gnu.gcc.help) + +<p>Another pre-processor based approach is to define a +macro <code>NAMESPACE_STD</code>, which is defined to either +"" or "std" based on a compile-type test. On GNU +systems, this can be done with autotools by means of an autoconf test +(see below) for <code>HAVE_NAMESPACE_STD</code>, then using that to +set a value for the <code>NAMESPACE_STD</code> macro. At that point, +one is able to use <code>NAMESPACE_STD::string</code>, which will +evaluate to <code>std::string</code> or +<code>::string</code> (ie, in the global namespace on systems that do +not put <code>string</code> in <code>std::</code>). </p> + +<pre style="background: #c0c0c0"> +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 +]) +</pre> + +<h5>Illegal iterator usage</h5> +<p> + The following illustrate implementation-allowed illegal iterator + use, and then correct use. +</p> + +<ul> <li><p>you cannot do + <code>ostream::operator<<(iterator)</code> to print the + address of the iterator => use <code>operator<< + &*iterator</code> instead + </p></li> +<li><p>you cannot clear an iterator's reference + (<code>iterator = 0</code>) => use + <code>iterator = iterator_type();</code> + </p></li> +<li><p> +<code>if (iterator)</code> won't work any + more => use <code>if (iterator != iterator_type())</code> + </p></li> +</ul> + +<h5><code>isspace</code> from <tt><cctype></tt> is a macro +</h5> + +<p> Glibc 2.0.x and 2.1.x define <tt><ctype.h></tt> +functionality as macros (isspace, isalpha etc.). +</p> + +<p> +This implementations of libstdc++, however, keep these functions as +macros, and so it is not back-portable to use fully qualified +names. For example: +</p> + +<pre> +#include <cctype> +int main() { std::isspace('X'); } +</pre> + +<p>Results in something like this: +</p> + +<pre> +std:: (__ctype_b[(int) ( ( 'X' ) )] & (unsigned short int) _ISspace ) ; +</pre> + + +<p> A solution is to modify a header-file so that the compiler tells +<tt><ctype.h></tt> to define functions instead of macros: +</p> + +<pre> +// This keeps isalnum, et al from being propagated as macros. +#if __linux__ +# define __NO_CTYPE 1 +#endif +</pre> + +<p>Then, include <ctype.h> +</p> + +<p> +Another problem arises if you put a <code>using namespace std;</code> +declaration at the top, and include <tt><ctype.h></tt>. This +will result in ambiguities between the definitions in the global +namespace (<tt><ctype.h></tt>) and the definitions in namespace +<code>std::</code> (<code><cctype></code>). +</p> + +<h5>No <code>vector::at</code>, <code>deque::at</code>, <code>string::at</code></h5> + +<p> + One solution is to add an autoconf-test for this: +</p> +<pre style="background: #c0c0c0"> +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("test_string"); +test_string.at(3); +], +[AC_MSG_RESULT(yes) +AC_DEFINE(HAVE_CONTAINER_AT)], +[AC_MSG_RESULT(no)]) +</pre> + +<p> +If you are using other (non-GNU) compilers it might be a good idea +to check for <code>string::at</code> separately. +</p> + +<h5>No <code>std::char_traits<char>::eof</code></h5> + +<p> +Use some kind of autoconf test, plus this: +</p> +<pre> +#ifdef HAVE_CHAR_TRAITS +#define CPP_EOF std::char_traits<char>::eof() +#else +#define CPP_EOF EOF +#endif +</pre> + +<h5>No <code>string::clear</code></h5> + +<p> + There are two functions for deleting the contents of a string: + <code>clear</code> and <code>erase</code> (the latter + returns the string). +</p> + +<pre> +void +clear() { _M_mutate(0, this->size(), 0); } +</pre> +<pre> +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()); +} +</pre> + +<p> + Unfortunately, ut <code>clear</code> is not + implemented in this version, so you should use + <code>erase</code> (which is probably faster than + <code>operator=(charT*)</code>). +</p> + +<h5>Removal of <code>ostream::form</code> and +<code>istream::scan</code> extensions</h5> + +<p> These are no longer supported. Please use + <a href="#sec-stringstream" title="Using stringstreams"> + stringstreams</a> instead. +</p> + +<h5>No <code>basic_stringbuf</code>, <code>basic_stringstream</code></h5> + +<p> +Although the ISO standard +<code>i/ostringstream</code>-classes are provided, (<tt><sstream></tt>), for compatibility with older implementations the pre-ISO <code>i/ostrstream</code> (<tt><strstream></tt>) interface is also provided, with these caveats: +</p> + + <div class="itemizedlist"><ul type="disc"> +<li><p> <code>strstream</code> is considered to be + deprecated + </p></li> +<li><p> <code>strstream</code> is limited to + <code>char</code> + </p></li> +<li><p> with <code>ostringstream</code> you don't + have to take care of terminating the string or freeing its + memory + </p></li> +<li><p> <code>istringstream</code> can be re-filled + (clear(); str(input);) + </p></li> +</ul></div> +<p> + You can then use output-stringstreams like this: +</p> + +<pre> +#ifdef HAVE_SSTREAM +# include <sstream> +#else +# include <strstream> +#endif + +#ifdef HAVE_SSTREAM + std::ostringstream oss; +#else + std::ostrstream oss; +#endif + +oss << "Name=" << m_name << ", number=" << 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 +</pre> + +<p> + Input-stringstreams can be used similarly: +</p> + +<pre> +std::string input; +... +#ifdef HAVE_SSTREAM +std::istringstream iss(input); +#else +std::istrstream iss(input.c_str()); +#endif + +int i; +iss >> i; +</pre> + +<p> One (the only?) restriction is that an istrstream cannot be re-filled: +</p> + +<pre> +std::istringstream iss(numerator); +iss >> m_num; +// this is not possible with istrstream +iss.clear(); +iss.str(denominator); +iss >> m_den; + </pre> + +<p> +If you don't care about speed, you can put these conversions in + a template-function: +</p> +<pre> +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; +} +</pre> + +<p> Another example of using stringstreams is in <a href="../21_strings/howto.html" target="_top">this howto</a>. +</p> + +<p> There is additional information in the libstdc++-v2 info files, in +particular "info iostream". +</p> + +<h5>Little or no wide character support</h5> + +<h5>No templatized iostreams</h5> + +<h5>Thread safety issues</h5> + +<p>This project is no longer maintained or supported, and the sources +archived. The code is considered replaced and rewritten. +</p> + + +<hr /> +<h3 class="left"> + <a name="v3">Third.</a> +</h3> +<p> The third generation GNU C++ library is called libstdc++, or +libstdc++-v3. +</p> + + <p>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. + </p> + + <p>A more formal description of the V3 goals can be found in the + official <a href="../17_intro/DESIGN">design document</a>. + </p> + +<p>Portability notes and known implementation limitations are as follows.</p> + +<h5>Pre-ISO headers moved to backwards or removed</h5> + +<p> The pre-ISO C++ headers + (<code>iostream.h</code>, <code>defalloc.h</code> etc.) are + available, unlike previous libstdc++ versions, but inclusion + generates a warning that you are using deprecated headers. +</p> + + <p>This compatibility layer is constructed by including the + standard C++ headers, and injecting any items in + <code>std::</code> into the global namespace. + </p> + <p>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 <a + href="http://www.parashift.com/c++-faq-lite/coding-standards.html#faq-27.4">item + [27.4]</a>. + </p> + +<p> Some include adjustment may be required. What follows is an +autoconf test that defines <code>PRE_STDCXX_HEADERS</code> when they +exist.</p> + +<pre style="background: #c0c0c0"> +# 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 "$ac_cv_cxx_pre_stdcxx" = yes; then + AC_DEFINE(PRE_STDCXX_HEADERS,,[Define if pre-ISO C++ header files are present. ]) + fi +]) +</pre> + +<p>Porting between pre-ISO headers and ISO headers is simple: headers +like <vector.h> can be replaced with <vector> and a using +directive <code>using namespace std;</code> can be put at the global +scope. This should be enough to get this code compiling, assuming the +other usage is correct. +</p> + +<h5>Extension headers hash_map, hash_set moved to ext or backwards</h5> + +<p> Header files <code>hash_map</code> and <code>hash_set</code> moved +to <code>ext/hash_map</code> and <code>ext/hash_set</code>, +respectively. At the same time, all types in these files are enclosed +in <code>namespace __gnu_cxx</code>. Later versions move deprecate +these files, and suggest using TR1's <code>unordered_map</code> +and <code>unordered_set</code> instead. +</p> + +<p>The following autoconf tests check for working HP/SGI hash containers. +</p> + +<pre style="background: #c0c0c0"> +# AC_HEADER_EXT_HASH_MAP +AC_DEFUN([AC_HEADER_EXT_HASH_MAP], [ + AC_CACHE_CHECK(for ext/hash_map, + ac_cv_cxx_ext_hash_map, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$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 "$ac_cv_cxx_ext_hash_map" = yes; then + AC_DEFINE(HAVE_EXT_HASH_MAP,,[Define if ext/hash_map is present. ]) + fi +]) +</pre> + +<pre style="background: #c0c0c0"> +# AC_HEADER_EXT_HASH_SET +AC_DEFUN([AC_HEADER_EXT_HASH_SET], [ + AC_CACHE_CHECK(for ext/hash_set, + ac_cv_cxx_ext_hash_set, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$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 +]) +</pre> + + +<h5> +No <code>ios::nocreate/ios::noreplace</code>. +</h5> + +<p> The existence of <code>ios::nocreate</code> 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. +</p> + +<p>For output streams, "nocreate" is probably the default, +unless you specify <code>std::ios::trunc</code> ? 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 <code>app</code>, <code>ate</code> +and <code>trunc</code> (except for <code>app</code> ?). +</p> + + +<h5> +No <code>stream::attach(int fd)</code> +</h5> + +<p> + 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. + </p> + +<p> + For a portable solution (among systems which use + filedescriptors), you need to implement a subclass of + <code>std::streambuf</code> (or + <code>std::basic_streambuf<..></code>) which opens a file + given a descriptor, and then pass an instance of this to the + stream-constructor. + </p> + +<p> + An extension is available that implements this. + <code><ext/stdio_filebuf.h></code> contains a derived class called + <a href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/class____gnu__cxx_1_1stdio__filebuf.html"><code>__gnu_cxx::stdio_filebuf</code></a>. + This class can be constructed from a C <code>FILE*</code> or a file + descriptor, and provides the <code>fd()</code> function. + </p> + +<p> + For another example of this, refer to + <a href="http://www.josuttis.com/cppcode/fdstream.html" target="_top">fdstream example</a> + by Nicolai Josuttis. +</p> + +<h5> +Support for C++98 dialect. +</h5> + +<p>Check for complete library coverage of the C++1998/2003 standard. +</p> + +<pre style="background: #c0c0c0"> + +# 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 +]) +</pre> + + +<h5> +Support for C++TR1 dialect. +</h5> + +<p>Check for library coverage of the TR1 standard. +</p> + +<pre style="background: #c0c0c0"> + +# 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 "$ac_cv_cxx_stdcxx_tr1" = yes; then + AC_DEFINE(STDCXX_TR1_HEADERS,,[Define if ISO C++ TR1 header files are present. ]) + fi +]) +</pre> + +<p>An alternative is to check just for specific TR1 includes, such as <unordered_map> and <unordered_set>. +</p> + +<pre style="background: #c0c0c0"> +# AC_HEADER_TR1_UNORDERED_MAP +AC_DEFUN([AC_HEADER_TR1_UNORDERED_MAP], [ + AC_CACHE_CHECK(for tr1/unordered_map, + ac_cv_cxx_tr1_unordered_map, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([#include <tr1/unordered_map>], [using std::tr1::unordered_map;], + ac_cv_cxx_tr1_unordered_map=yes, ac_cv_cxx_tr1_unordered_map=no) + AC_LANG_RESTORE + ]) + if test "$ac_cv_cxx_tr1_unordered_map" = yes; then + AC_DEFINE(HAVE_TR1_UNORDERED_MAP,,[Define if tr1/unordered_map is present. ]) + fi +]) +</pre> + +<pre style="background: #c0c0c0"> +# 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 "$ac_cv_cxx_tr1_unordered_set" = yes; then + AC_DEFINE(HAVE_TR1_UNORDERED_SET,,[Define if tr1/unordered_set is present. ]) + fi +]) +</pre> + + + +<h5> +Support for C++0x dialect. +</h5> + +<p>Check for baseline language coverage in the compiler for the C++0xstandard. +</p> + +<pre style="background: #c0c0c0"> +# AC_COMPILE_STDCXX_OX +AC_DEFUN([AC_COMPILE_STDCXX_0X], [ + AC_CACHE_CHECK(if g++ supports C++0x features without additional flags, + ac_cv_cxx_compile_cxx0x_native, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_TRY_COMPILE([ + template <typename T> + struct check + { + static_assert(sizeof(int) <= sizeof(T), "not big enough"); + }; + + typedef check<check<bool>> right_angle_brackets; + + int a; + decltype(a) b; + + typedef check<int> check_type; + check_type c; + check_type&& cr = c;],, + ac_cv_cxx_compile_cxx0x_native=yes, ac_cv_cxx_compile_cxx0x_native=no) + AC_LANG_RESTORE + ]) + + AC_CACHE_CHECK(if g++ supports C++0x features with -std=c++0x, + ac_cv_cxx_compile_cxx0x_cxx, + [AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$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 +]) +</pre> + + +<p>Check for library coverage of the C++0xstandard. +</p> + +<pre style="background: #c0c0c0"> + +# 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 +]) +</pre> + +<p>As is the case for TR1 support, these autoconf macros can be made for a finer-grained, per-header-file check. For <unordered_map> +</p> + +<pre style="background: #c0c0c0"> + +# 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 +]) +</pre> + +<pre style="background: #c0c0c0"> +# 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 +]) +</pre> + + +<h5> +Container iterator_type is not necessarily container value_type* +</h5> + + +<hr /> +<h3 class="left"> + <a name="v4">Fourth, and future</a> +</h3> + +<hr /> +<h3 class="left"> + <a name="Links">Links</a> +</h3> + +<p> +<a href="http://www.kegel.com/gcc/gcc4.html">Migrating to gcc-4.1</a>, by Dan Kegel. +</p> + +<p> +<a href="http://lists.debian.org/debian-gcc/2006/03/msg00405.html">Building the whole Debian archive with GCC 4.1: a summary</a>, by Martin Michlmayr +</p> + +<p> +<a href="http://annwm.lbl.gov/~leggett/Atlas/gcc-3.2.html">Migration guide for GCC-3.2</a> +</p> + +</body> +</html> + |
