diff --git a/pom.xml b/pom.xml
index dbbe787..eea9407 100644
--- a/pom.xml
+++ b/pom.xml
@@ -79,7 +79,7 @@
     <dependency>
       <groupId>com.github.jnr</groupId>
       <artifactId>jnr-ffi</artifactId>
-      <version>2.2.10</version>
+      <version>2.2.11-SNAPSHOT</version>
     </dependency>
     <dependency>
       <groupId>com.github.jnr</groupId>
diff --git a/src/main/java/jnr/posix/LibC.java b/src/main/java/jnr/posix/LibC.java
index 6df0ffd..fb384e7 100644
--- a/src/main/java/jnr/posix/LibC.java
+++ b/src/main/java/jnr/posix/LibC.java
@@ -85,10 +85,14 @@ public interface LibC {
     int dup(int fd);
     int dup2(int oldFd, int newFd);
 
+    @Variadic(fixedCount = 2)
     int fcntl(int fd, int fnctl, Flock arg);
+    @Variadic(fixedCount = 2)
     int fcntl(int fd, int fnctl, Pointer arg);
+    @Variadic(fixedCount = 2)
     int fcntl(int fd, int fnctl);
-    int fcntl(int fd, int fnctl, int arg);
+    @Variadic(fixedCount = 2)
+    int fcntl(int fd, int fnctl, @u_int64_t int arg);
     @Deprecated
     int fcntl(int fd, int fnctl, int... arg);
     int access(CharSequence path, int amode);
@@ -164,7 +168,8 @@ public interface LibCSignalHandler {
     
     int flock(int fd, int mode);
     int unlink(CharSequence path);
-    int open(CharSequence path, int flags, int perm);
+    @Variadic(fixedCount = 2)
+    int open(CharSequence path, int flags, @u_int32_t int perm);
     int pipe(@Out int[] fds);
     int truncate(CharSequence path, long length);
     int ftruncate(int fd, long offset);
diff --git a/src/test/java/jnr/posix/FileTest.java b/src/test/java/jnr/posix/FileTest.java
index 98981b3..afadb07 100644
--- a/src/test/java/jnr/posix/FileTest.java
+++ b/src/test/java/jnr/posix/FileTest.java
@@ -380,6 +380,15 @@ public void openTest() throws Throwable {
 
         result = posix.close(fd);
         assertEquals(-1, result);
+
+        fd = posix.open("jnr-posix-filetest.txt", OpenFlags.O_CREAT.intValue() | OpenFlags.O_RDWR.intValue(), 0600);
+
+        assertEquals(0600, posix.stat("jnr-posix-filetest.txt").mode() & 0777);
+
+        result = posix.close(fd);
+        assertEquals(0, result);
+
+        new File("jnr-posix-filetest.txt").delete();
     }
 
     @Test