diff --git a/samples/nonBlockingEchoServer/EchoServer.kt b/samples/nonBlockingEchoServer/EchoServer.kt
index 5f298987dd4..141ec6a0dc4 100644
--- a/samples/nonBlockingEchoServer/EchoServer.kt
+++ b/samples/nonBlockingEchoServer/EchoServer.kt
@@ -203,22 +203,15 @@ class IOException: RuntimeException {
 }
 
 val errno: Int
-    get() = __error()!!.pointed.value
+    get() = interop_errno()
 
-fun FD_ZERO(set: fd_set) {
-    memset(set.fds_bits, 0, sizeOf<fd_set>())
-}
+fun FD_ZERO(set: fd_set): Unit = interop_FD_ZERO(set.ptr)
 
-fun FD_SET(bit: Int, set: fd_set) {
-    set.fds_bits[bit / 32] = set.fds_bits[bit / 32] or (1 shl (bit % 32))
-}
+fun FD_SET(bit: Int, set: fd_set): Unit = interop_FD_SET(bit, set.ptr)
 
-fun FD_ISSET(bit: Int, set: fd_set): Boolean {
-    return set.fds_bits[bit / 32] and (1 shl (bit % 32)) != 0
-}
+fun FD_ISSET(bit: Int, set: fd_set) = interop_FD_ISSET(bit, set.ptr) != 0
 
-// Not available through interop because declared as macro:
-fun htons(value: Short) = ((value.toInt() ushr 8) or (value.toInt() shl 8)).toShort()
+fun htons(value: Short) = interop_htons(value.toInt()).toShort()
 
 fun getUnixError() = strerror(errno)!!.toKString()
 
diff --git a/samples/nonBlockingEchoServer/sockets.def b/samples/nonBlockingEchoServer/sockets.def
index 3f8f2666168..29d04ef2609 100644
--- a/samples/nonBlockingEchoServer/sockets.def
+++ b/samples/nonBlockingEchoServer/sockets.def
@@ -1,2 +1,24 @@
 headers = sys/socket.h sys/errno.h sys/select.h fcntl.h netdb.h stdio.h string.h unistd.h stdlib.h netinet/in.h
 excludeDependentModules.osx = true
+
+---
+
+static int interop_errno() {
+	return errno;
+}
+
+static int interop_htons(int x) {
+	return htons(x);
+}
+
+static void interop_FD_ZERO(fd_set *set) {
+	FD_ZERO(set);
+}
+
+static void interop_FD_SET(int bit, fd_set *set) {
+	FD_SET(bit, set);
+}
+
+static int interop_FD_ISSET(int bit, fd_set *set) {
+	return FD_ISSET(bit, set);
+}
diff --git a/samples/socket/EchoServer.kt b/samples/socket/EchoServer.kt
index 2b8e5ae6e06..d7a776cac9d 100644
--- a/samples/socket/EchoServer.kt
+++ b/samples/socket/EchoServer.kt
@@ -64,24 +64,21 @@ fun main(args: Array<String>) {
     }
 }
 
-// Not available through interop because declared as macro:
-fun htons(value: Short) = ((value.toInt() ushr 8) or (value.toInt() shl 8)).toShort()
+val errno: Int
+    get() = interop_errno()
 
-fun throwUnixError(): Nothing {
-    perror(null) // TODO: store error message to exception instead.
-    throw Error("UNIX call failed")
-}
+fun htons(value: Short) = interop_htons(value.toInt()).toShort()
 
 inline fun Int.ensureUnixCallResult(predicate: (Int) -> Boolean): Int {
     if (!predicate(this)) {
-        throwUnixError()
+        throw Error(strerror(errno)!!.toKString())
     }
     return this
 }
 
 inline fun Long.ensureUnixCallResult(predicate: (Long) -> Boolean): Long {
     if (!predicate(this)) {
-        throwUnixError()
+        throw Error(strerror(errno)!!.toKString())
     }
     return this
 }
\ No newline at end of file
diff --git a/samples/socket/sockets.def b/samples/socket/sockets.def
index c6e28130bb0..9d9821313f6 100644
--- a/samples/socket/sockets.def
+++ b/samples/socket/sockets.def
@@ -1,2 +1,12 @@
-headers = sys/socket.h netdb.h stdio.h string.h unistd.h stdlib.h netinet/in.h
+headers = sys/socket.h sys/errno.h netdb.h stdio.h string.h unistd.h stdlib.h netinet/in.h
 excludeDependentModules.osx = true
+
+---
+
+static int interop_errno() {
+        return errno;
+}
+
+static int interop_htons(int x) {
+	return htons(x);
+}