Fix integer conversion warnings on 64-bit Windows.
diff --git a/asio/src/tests/unit/generic/datagram_protocol.cpp b/asio/src/tests/unit/generic/datagram_protocol.cpp
index 081dca4..24ab9d3 100644
--- a/asio/src/tests/unit/generic/datagram_protocol.cpp
+++ b/asio/src/tests/unit/generic/datagram_protocol.cpp
@@ -73,7 +73,8 @@
     dp::socket socket2(ios, dp(af_inet, ipproto_udp));
     dp::socket socket3(ios, dp::endpoint());
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(af_inet, sock_dgram, 0);
+    dp::socket::native_handle_type native_socket1
+      = ::socket(af_inet, sock_dgram, 0);
     dp::socket socket4(ios, dp(af_inet, ipproto_udp), native_socket1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -105,9 +106,11 @@
     socket1.open(dp(af_inet, ipproto_udp), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(af_inet, sock_dgram, 0);
+    dp::socket::native_handle_type native_socket2
+      = ::socket(af_inet, sock_dgram, 0);
     socket1.assign(dp(af_inet, ipproto_udp), native_socket2);
-    int native_socket3 = ::socket(af_inet, sock_dgram, 0);
+    dp::socket::native_handle_type native_socket3
+      = ::socket(af_inet, sock_dgram, 0);
     socket1.assign(dp(af_inet, ipproto_udp), native_socket3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
diff --git a/asio/src/tests/unit/generic/raw_protocol.cpp b/asio/src/tests/unit/generic/raw_protocol.cpp
index b8ebfd1..fd8dd4f 100644
--- a/asio/src/tests/unit/generic/raw_protocol.cpp
+++ b/asio/src/tests/unit/generic/raw_protocol.cpp
@@ -73,7 +73,8 @@
     rp::socket socket2(ios, rp(af_inet, ipproto_icmp));
     rp::socket socket3(ios, rp::endpoint());
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(af_inet, sock_raw, 0);
+    rp::socket::native_handle_type native_socket1
+      = ::socket(af_inet, sock_raw, 0);
     rp::socket socket4(ios, rp(af_inet, ipproto_icmp), native_socket1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -105,9 +106,11 @@
     socket1.open(rp(af_inet, ipproto_icmp), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(af_inet, sock_raw, 0);
+    rp::socket::native_handle_type native_socket2
+      = ::socket(af_inet, sock_raw, 0);
     socket1.assign(rp(af_inet, ipproto_icmp), native_socket2);
-    int native_socket3 = ::socket(af_inet, sock_raw, 0);
+    rp::socket::native_handle_type native_socket3
+      = ::socket(af_inet, sock_raw, 0);
     socket1.assign(rp(af_inet, ipproto_icmp), native_socket3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
diff --git a/asio/src/tests/unit/generic/seq_packet_protocol.cpp b/asio/src/tests/unit/generic/seq_packet_protocol.cpp
index 8d1fc38..61222dd 100644
--- a/asio/src/tests/unit/generic/seq_packet_protocol.cpp
+++ b/asio/src/tests/unit/generic/seq_packet_protocol.cpp
@@ -72,7 +72,8 @@
     spp::socket socket2(ios, spp(af_inet, 0));
     spp::socket socket3(ios, spp::endpoint());
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(af_inet, sock_seqpacket, 0);
+    spp::socket::native_handle_type native_socket1
+      = ::socket(af_inet, sock_seqpacket, 0);
     spp::socket socket4(ios, spp(af_inet, 0), native_socket1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -101,9 +102,11 @@
     socket1.open(spp(af_inet, 0), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(af_inet, sock_seqpacket, 0);
+    spp::socket::native_handle_type native_socket2
+      = ::socket(af_inet, sock_seqpacket, 0);
     socket1.assign(spp(af_inet, 0), native_socket2);
-    int native_socket3 = ::socket(af_inet, sock_seqpacket, 0);
+    spp::socket::native_handle_type native_socket3
+      = ::socket(af_inet, sock_seqpacket, 0);
     socket1.assign(spp(af_inet, 0), native_socket3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
diff --git a/asio/src/tests/unit/generic/stream_protocol.cpp b/asio/src/tests/unit/generic/stream_protocol.cpp
index 3ae2eb7..6db459c 100644
--- a/asio/src/tests/unit/generic/stream_protocol.cpp
+++ b/asio/src/tests/unit/generic/stream_protocol.cpp
@@ -83,7 +83,8 @@
 #if defined(ASIO_WINDOWS_RUNTIME)
     Windows::Networking::Sockets::StreamSocket^ native_socket1 = nullptr;
 #else // defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(af_inet, sock_stream, 0);
+    sp::socket::native_handle_type native_socket1
+      = ::socket(af_inet, sock_stream, 0);
 #endif // defined(ASIO_WINDOWS_RUNTIME)
     sp::socket socket4(ios, sp(af_inet, ipproto_tcp), native_socket1);
 
@@ -117,13 +118,15 @@
 #if defined(ASIO_WINDOWS_RUNTIME)
     Windows::Networking::Sockets::StreamSocket^ native_socket2 = nullptr;
 #else // defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(af_inet, sock_stream, 0);
+    sp::socket::native_handle_type native_socket2
+      = ::socket(af_inet, sock_stream, 0);
 #endif // defined(ASIO_WINDOWS_RUNTIME)
     socket1.assign(sp(af_inet, ipproto_tcp), native_socket2);
 #if defined(ASIO_WINDOWS_RUNTIME)
     Windows::Networking::Sockets::StreamSocket^ native_socket3 = nullptr;
 #else // defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket3 = ::socket(af_inet, sock_stream, 0);
+    sp::socket::native_handle_type native_socket3
+      = ::socket(af_inet, sock_stream, 0);
 #endif // defined(ASIO_WINDOWS_RUNTIME)
     socket1.assign(sp(af_inet, ipproto_tcp), native_socket3, ec);
 
diff --git a/asio/src/tests/unit/ip/icmp.cpp b/asio/src/tests/unit/ip/icmp.cpp
index 7e13223..b8cc2e8 100644
--- a/asio/src/tests/unit/ip/icmp.cpp
+++ b/asio/src/tests/unit/ip/icmp.cpp
@@ -96,7 +96,8 @@
     ip::icmp::socket socket4(ios, ip::icmp::endpoint(ip::icmp::v4(), 0));
     ip::icmp::socket socket5(ios, ip::icmp::endpoint(ip::icmp::v6(), 0));
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    ip::icmp::socket::native_handle_type native_socket1
+      = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     ip::icmp::socket socket6(ios, ip::icmp::v4(), native_socket1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -132,9 +133,11 @@
     socket1.open(ip::icmp::v6(), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    ip::icmp::socket::native_handle_type native_socket2
+      = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     socket1.assign(ip::icmp::v4(), native_socket2);
-    int native_socket3 = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    ip::icmp::socket::native_handle_type native_socket3
+      = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     socket1.assign(ip::icmp::v4(), native_socket3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
diff --git a/asio/src/tests/unit/ip/tcp.cpp b/asio/src/tests/unit/ip/tcp.cpp
index cc14f05..de710e2 100644
--- a/asio/src/tests/unit/ip/tcp.cpp
+++ b/asio/src/tests/unit/ip/tcp.cpp
@@ -244,7 +244,8 @@
     ip::tcp::socket socket4(ios, ip::tcp::endpoint(ip::tcp::v4(), 0));
     ip::tcp::socket socket5(ios, ip::tcp::endpoint(ip::tcp::v6(), 0));
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    ip::tcp::socket::native_handle_type native_socket1
+      = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     ip::tcp::socket socket6(ios, ip::tcp::v4(), native_socket1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -283,9 +284,11 @@
     socket1.open(ip::tcp::v6(), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    ip::tcp::socket::native_handle_type native_socket2
+      = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     socket1.assign(ip::tcp::v4(), native_socket2);
-    int native_socket3 = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    ip::tcp::socket::native_handle_type native_socket3
+      = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     socket1.assign(ip::tcp::v4(), native_socket3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -739,7 +742,8 @@
     ip::tcp::acceptor acceptor4(ios, ip::tcp::endpoint(ip::tcp::v4(), 0));
     ip::tcp::acceptor acceptor5(ios, ip::tcp::endpoint(ip::tcp::v6(), 0));
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_acceptor1 = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    ip::tcp::acceptor::native_handle_type native_acceptor1
+      = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     ip::tcp::acceptor acceptor6(ios, ip::tcp::v4(), native_acceptor1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -767,9 +771,11 @@
     acceptor1.open(ip::tcp::v6(), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_acceptor2 = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    ip::tcp::acceptor::native_handle_type native_acceptor2
+      = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     acceptor1.assign(ip::tcp::v4(), native_acceptor2);
-    int native_acceptor3 = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    ip::tcp::acceptor::native_handle_type native_acceptor3
+      = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     acceptor1.assign(ip::tcp::v4(), native_acceptor3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
diff --git a/asio/src/tests/unit/ip/udp.cpp b/asio/src/tests/unit/ip/udp.cpp
index aac6fd9..4c72ede 100644
--- a/asio/src/tests/unit/ip/udp.cpp
+++ b/asio/src/tests/unit/ip/udp.cpp
@@ -112,7 +112,8 @@
     ip::udp::socket socket4(ios, ip::udp::endpoint(ip::udp::v4(), 0));
     ip::udp::socket socket5(ios, ip::udp::endpoint(ip::udp::v6(), 0));
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket1 = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    ip::udp::socket::native_handle_type native_socket1
+      = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     ip::udp::socket socket6(ios, ip::udp::v4(), native_socket1);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)
 
@@ -151,9 +152,11 @@
     socket1.open(ip::udp::v6(), ec);
 
 #if !defined(ASIO_WINDOWS_RUNTIME)
-    int native_socket2 = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    ip::udp::socket::native_handle_type native_socket2
+      = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     socket1.assign(ip::udp::v4(), native_socket2);
-    int native_socket3 = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    ip::udp::socket::native_handle_type native_socket3
+      = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
     socket1.assign(ip::udp::v4(), native_socket3, ec);
 #endif // !defined(ASIO_WINDOWS_RUNTIME)