[committed,2/3] libstdc++ Clarify argument to net::io_context::async_wait

commit 3517dfe05c05a48885149334143230fcf0ebe6be
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Apr 23 13:31:33 2021

    libstdc++: Clarify argument to net::io_context::async_wait
    
    Add a comment documenting the __w parameter of the private
    ios_context::async_wait function. Add casts to callers, making the
    conversions explicit.
    
    libstdc++-v3/ChangeLog:
    
            * include/experimental/io_context (io_context::async_wait): Add
            comment.
            * include/experimental/socket (basic_socket::async_connect):
            Cast wait_type constant to int.
            (basic_datagram_socket::async_receive): Likewise.
            (basic_datagram_socket::async_receive_from): Likewise.
            (basic_datagram_socket::async_send): Likewise.
            (basic_datagram_socket::async_send_to): Likewise.
            (basic_stream_socket::async_receive): Likewise.
            (basic_stream_socket::async_send): Likewise. Use io_context
            parameter directly, instead of via an executor.
            (basic_socket_acceptor::async_accept): Likewise.

diff --git a/libstdc++-v3/include/experimental/io_context b/libstdc++-v3/include/experimental/io_context
index c82f30cd119..82d7b4f545e 100644
--- a/libstdc++-v3/include/experimental/io_context
+++ b/libstdc++-v3/include/experimental/io_context
@@ -475,6 +475,9 @@  inline namespace v1
 	return 0;
       }
 
+    // The caller must know what the wait-type __w will be interpreted.
+    // In the current implementation the reactor is based on <poll.h>
+    // so the parameter must be one of POLLIN, POLLOUT or POLLERR.
     template<typename _Op>
       void
       async_wait(int __fd, int __w, _Op&& __op)
diff --git a/libstdc++-v3/include/experimental/socket b/libstdc++-v3/include/experimental/socket
index ec4ed9d95e2..09c3b729607 100644
--- a/libstdc++-v3/include/experimental/socket
+++ b/libstdc++-v3/include/experimental/socket
@@ -954,7 +954,7 @@  inline namespace v1
 	    }
 
 	  get_executor().context().async_wait( native_handle(),
-	      socket_base::wait_read,
+	      (int) socket_base::wait_read,
 	      [__h = std::move(__init.completion_handler),
                __ep = std::move(__endpoint),
                __fd = native_handle()]
@@ -1165,7 +1165,7 @@  inline namespace v1
             __init{__token};
 
 	  this->get_executor().context().async_wait(this->native_handle(),
-	      socket_base::wait_read,
+	      (int) socket_base::wait_read,
 	      [__h = std::move(__init.completion_handler),
                &__buffers, __flags = static_cast<int>(__flags),
                __fd = this->native_handle()]
@@ -1271,7 +1271,7 @@  inline namespace v1
             __init{__token};
 
 	  this->get_executor().context().async_wait( this->native_handle(),
-	      socket_base::wait_read,
+	      (int) socket_base::wait_read,
 	      [__h = std::move(__init.completion_handler),
                &__buffers, __flags = static_cast<int>(__flags),
                __sender = std::move(__sender),
@@ -1366,7 +1366,7 @@  inline namespace v1
             __init{__token};
 
 	  this->get_executor().context().async_wait( this->native_handle(),
-	      socket_base::wait_write,
+	      (int) socket_base::wait_write,
 	      [__h = std::move(__init.completion_handler),
                &__buffers, __flags = static_cast<int>(__flags),
                __fd = this->native_handle()]
@@ -1469,7 +1469,7 @@  inline namespace v1
             __init{__token};
 
 	  this->get_executor().context().async_wait( this->native_handle(),
-	      socket_base::wait_write,
+	      (int) socket_base::wait_write,
 	      [__h = std::move(__init.completion_handler),
                &__buffers, __flags = static_cast<int>(__flags),
                __recipient = std::move(__recipient),
@@ -1634,7 +1634,7 @@  inline namespace v1
 	    }
 
           this->get_executor().context().async_wait(this->native_handle(),
-	      socket_base::wait_read,
+	      (int) socket_base::wait_read,
 	      [__h = std::move(__init.completion_handler),
                &__buffers, __flags = static_cast<int>(__flags),
                __fd = this->native_handle()]
@@ -1741,7 +1741,7 @@  inline namespace v1
 	    }
 
           this->get_executor().context().async_wait(this->native_handle(),
-	      socket_base::wait_write,
+	      (int) socket_base::wait_write,
 	      [__h = std::move(__init.completion_handler),
                &__buffers, __flags = static_cast<int>(__flags),
                __fd = this->native_handle()]
@@ -2098,8 +2098,8 @@  inline namespace v1
           async_completion<_CompletionToken, void(error_code, socket_type)>
             __init{__token};
 
-	  __ctx.get_executor().context().async_wait(native_handle(),
-	      socket_base::wait_read,
+	  __ctx.async_wait(native_handle(),
+	      (int) socket_base::wait_read,
 	      [__h = std::move(__init.completion_handler),
                __connabort = enable_connection_aborted(),
                __fd = native_handle(),
@@ -2189,8 +2189,8 @@  inline namespace v1
           async_completion<_CompletionToken, void(error_code, socket_type)>
             __init{__token};
 
-	  __ctx.get_executor().context().async_wait(native_handle(),
-	      socket_base::wait_read,
+	  __ctx.async_wait(native_handle(),
+	      (int) socket_base::wait_read,
 	      [__h = std::move(__init.completion_handler),
               __ep = std::move(__endpoint),
                __connabort = enable_connection_aborted(),