Updated deprecated uses of boost/bind.hpp, replaced standard function wrappers.

boost/bind.hpp generates deprecation warnings about global placeholder argument
keywords. This commit updates to boost/bind/bind.hpp and namespaced keywords.

Also, this commit replaces standard function object wrappers, which were removed
from C++20, with boost::bind.

Author: Lastique

example/options_heirarchy.cpp

@@ -21,12 +21,14 @@
 //
 
 #include <boost/program_options.hpp>
-namespace po = boost::program_options;
 #include <string>
 #include <iostream>
 #include <map>
 #include <stdexcept>
 #include <fstream>
+#include <boost/bind/bind.hpp>
+
+namespace po = boost::program_options;
 
 const std::string version("1.0");
 
@@ -221,7 +223,7 @@ class OptionsHeirarchy
          // The next two lines are the crazy syntax to use EnvironmentMapper as
          // the lookup function for env->config name conversions
          boost::function1<std::string, std::string>(
-         std::bind1st(std::mem_fun(&OptionsHeirarchy::EnvironmentMapper), this))),
+         boost::bind(&OptionsHeirarchy::EnvironmentMapper, this))),
          results);
       notify(results);
    }

src/cmdline.cpp

@@ -228,24 +228,24 @@ namespace boost { namespace program_options { namespace detail {
 
         if (m_additional_parser)
             style_parsers.push_back(
-                boost::bind(&cmdline::handle_additional_parser, this, _1));
+                boost::bind(&cmdline::handle_additional_parser, this, boost::placeholders::_1));
 
         if (m_style & allow_long)
             style_parsers.push_back(
-                boost::bind(&cmdline::parse_long_option, this, _1));
+                boost::bind(&cmdline::parse_long_option, this, boost::placeholders::_1));
 
         if ((m_style & allow_long_disguise))
             style_parsers.push_back(
-                boost::bind(&cmdline::parse_disguised_long_option, this, _1));
+                boost::bind(&cmdline::parse_disguised_long_option, this, boost::placeholders::_1));
 
         if ((m_style & allow_short) && (m_style & allow_dash_for_short))
             style_parsers.push_back(
-                boost::bind(&cmdline::parse_short_option, this, _1));
+                boost::bind(&cmdline::parse_short_option, this, boost::placeholders::_1));
 
         if ((m_style & allow_short) && (m_style & allow_slash_for_short))
-            style_parsers.push_back(boost::bind(&cmdline::parse_dos_option, this, _1));
+            style_parsers.push_back(boost::bind(&cmdline::parse_dos_option, this, boost::placeholders::_1));
 
-        style_parsers.push_back(boost::bind(&cmdline::parse_terminator, this, _1));
+        style_parsers.push_back(boost::bind(&cmdline::parse_terminator, this, boost::placeholders::_1));
 
         vector<option> result;
         vector<string>& args = m_args;

src/convert.cpp

@@ -92,6 +92,7 @@ namespace boost {
     from_8_bit(const std::string& s, 
                const std::codecvt<wchar_t, char, std::mbstate_t>& cvt)
     {
+        using namespace boost::placeholders;
         return detail::convert<wchar_t>(
             s,                 
             boost::bind(&std::codecvt<wchar_t, char, mbstate_t>::in,
@@ -103,6 +104,7 @@ namespace boost {
     to_8_bit(const std::wstring& s, 
              const std::codecvt<wchar_t, char, std::mbstate_t>& cvt)
     {
+        using namespace boost::placeholders;
         return detail::convert<char>(
             s,                 
             boost::bind(&codecvt<wchar_t, char, mbstate_t>::out,

src/parsers.cpp

@@ -78,12 +78,12 @@ namespace boost { namespace program_options {
 
             std::transform(opt.value.begin(), opt.value.end(),
                            back_inserter(result.value),
-                           boost::bind(from_utf8, _1));
+                           boost::bind(from_utf8, boost::placeholders::_1));
 
             std::transform(opt.original_tokens.begin(), 
                            opt.original_tokens.end(),
                            back_inserter(result.original_tokens),
-                           boost::bind(from_utf8, _1));
+                           boost::bind(from_utf8, boost::placeholders::_1));
             return result;
         }
     }

test/test_convert.cpp

@@ -13,8 +13,6 @@
 #include <sstream>
 #include <iostream>
 #include <boost/progress.hpp>
-#include <boost/bind.hpp>
-#include <boost/ref.hpp>
 
 #include <boost/program_options/detail/convert.hpp>
 #include <boost/program_options/detail/utf8_codecvt_facet.hpp>