zombie reap fix.

closes #256

include/boost/process/detail/config.hpp

@@ -21,7 +21,9 @@
 #include <system_error>
 #include <boost/system/api_config.hpp>
 
+#include <boost/throw_exception.hpp>
 #include <boost/process/exception.hpp>
+#include <boost/assert/source_location.hpp>
 
 #if defined(BOOST_POSIX_API)
 #include <errno.h>
@@ -71,31 +73,33 @@ inline std::error_code get_last_error() noexcept
 }
 #endif
 
-inline void throw_last_error(const std::string & msg)
+inline void throw_last_error(const std::string & msg, boost::source_location const & loc = boost::source_location())
 {
-    throw process_error(get_last_error(), msg);
+    boost::throw_exception(process_error(get_last_error(), msg), loc);
 }
 
-inline void throw_last_error(const char * msg)
+inline void throw_last_error(const char * msg, boost::source_location const & loc = boost::source_location())
 {
-    throw process_error(get_last_error(), msg);
+    boost::throw_exception(process_error(get_last_error(), msg), loc);
 }
 
-inline void throw_last_error()
+inline void throw_last_error(boost::source_location const & loc = boost::source_location())
 {
-    throw process_error(get_last_error());
+    boost::throw_exception(process_error(get_last_error()), loc);
 }
 
-inline void throw_error(const std::error_code& ec)
+inline void throw_error(const std::error_code& ec,
+                        boost::source_location const & loc = boost::source_location())
 {
     if (ec)
-        throw process_error(ec);
+        boost::throw_exception(process_error(ec), loc);
 }
 
-inline void throw_error(const std::error_code& ec, const char* msg)
+inline void throw_error(const std::error_code& ec, const char* msg,
+                        boost::source_location const & loc = boost::source_location())
 {
     if (ec)
-        throw process_error(ec, msg);
+        boost::throw_exception(process_error(ec, msg), loc);
 }
 
 template<typename Char> constexpr Char null_char();

include/boost/process/detail/posix/async_out.hpp

@@ -71,7 +71,7 @@ struct async_out_buffer : ::boost::process::detail::posix::handler_base_ext,
     }
 
     template <typename Executor>
-    inline void on_success(Executor &exec)
+    inline void on_success(Executor &)
     {
         auto  pipe              = this->pipe;
         boost::asio::async_read(*pipe, buf,

include/boost/process/detail/posix/executor.hpp

@@ -445,7 +445,7 @@ child executor<Sequence>::invoke(boost::mpl::false_, boost::mpl::false_)
     if (_ec)
     {
         //if an error occurred we need to reap the child process
-        ::waitpid(this->pid, nullptr, WNOHANG);
+        ::waitpid(this->pid, nullptr, 0);
         boost::fusion::for_each(seq, call_on_error(*this, _ec));
         return child();
     }

include/boost/process/detail/windows/basic_cmd.hpp

@@ -61,6 +61,10 @@ inline std::string build_args(const std::string & exe, std::vector<std::string>
                 arg += '"';
             }
         }
+        else
+        {
+            arg = "\"\"";
+        }
 
         if (!st.empty())//first one does not need a preceding space
             st += ' ';
@@ -105,6 +109,10 @@ inline std::wstring build_args(const std::wstring & exe, std::vector<std::wstrin
                 arg += '"';
             }
         }
+        else
+        {
+            arg = L"\"\"";
+        }
 
         if (!st.empty())//first one does not need a preceding space
             st += L' ';

include/boost/process/v2/environment.hpp

@@ -1805,6 +1805,7 @@ struct process_environment
   }
 
 
+  BOOST_PROCESS_V2_DECL
   error_code on_setup(posix::default_launcher & launcher, 
                       const filesystem::path &, const char * const *);
 
@@ -1886,6 +1887,8 @@ struct hash<BOOST_PROCESS_V2_NAMESPACE::environment::key_value_pair>
 
 #if defined(BOOST_PROCESS_V2_HEADER_ONLY)
 
+
+#include <boost/process/v2/impl/environment.ipp>
 #include <boost/process/v2/detail/impl/environment.ipp>
 
 #endif