diff --git a/include/stdlib.h b/include/stdlib.h
index 81e939670d..745f4286b5 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -223,6 +223,7 @@ int       posix_memalign(FAR void **, size_t, size_t);
 /* Pseudo-Terminals */
 
 #ifdef CONFIG_PSEUDOTERM
+int       posix_openpt(int oflag);
 FAR char *ptsname(int fd);
 int       ptsname_r(int fd, FAR char *buf, size_t buflen);
 int       unlockpt(int fd);
diff --git a/libs/libc/stdlib/lib_openpty.c b/libs/libc/stdlib/lib_openpty.c
index e0332105c8..9b8e9bfe45 100644
--- a/libs/libc/stdlib/lib_openpty.c
+++ b/libs/libc/stdlib/lib_openpty.c
@@ -32,13 +32,43 @@
 #include <nuttx/serial/pty.h>
 
 /****************************************************************************
- * Private Functions
+ * Public Functions
  ****************************************************************************/
 
-static int openmaster(void)
+/****************************************************************************
+ * Name: posix_openpt
+ *
+ * Description:
+ *   The posix_openpt() function establish a connection between a master
+ *   device for a pseudo-terminal and a file descriptor. The file descriptor
+ *   is used by other I/O functions that refer to that pseudo-terminal.
+ *
+ *   The file status flags and file access modes of the open file description
+ *   shall be set according to the value of oflag.
+ *
+ *   Values for oflag are constructed by a bitwise-inclusive OR of flags from
+ *   the following list, defined in <fcntl.h>:
+ *
+ *   O_RDWR
+ *       Open for reading and writing.
+ *   O_NOCTTY
+ *       If set posix_openpt() shall not cause the terminal device to become
+ *       the controlling terminal for the process.
+ *
+ *   The behavior of other values for the oflag argument is unspecified.
+ *
+ * Returned Value:
+ *   Upon successful completion, the posix_openpt() function shall open
+ *   a master pseudo-terminal device and return a non-negative integer
+ *   representing the lowest numbered unused file descriptor. Otherwise,
+ *   -1 shall be returned and errno set to indicate the error.
+ *
+ ****************************************************************************/
+
+int posix_openpt(int oflag)
 {
 #ifdef CONFIG_PSEUDOTERM_SUSV1
-  return open("dev/ptmx", O_RDWR);
+  return open("dev/ptmx", oflag);
 #else
   int minor;
 
@@ -48,13 +78,13 @@ static int openmaster(void)
       int fd;
 
       snprintf(devname, 16, "/dev/pty%d", minor);
-      fd = open(devname, O_RDWR);
+      fd = open(devname, oflag);
       if (fd < 0)
         {
           /* Fail, register and try again */
 
           pty_register(minor);
-          fd = open(devname, O_RDWR);
+          fd = open(devname, oflag);
         }
 
       if (fd >= 0)
@@ -67,10 +97,6 @@ static int openmaster(void)
 #endif
 }
 
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
 /****************************************************************************
  * Name: openpty
  *
@@ -83,8 +109,8 @@ static int openmaster(void)
  *   the slave will be set to the values in win.
  *
  * Returned Value:
- *  If a call to openpty() is not successful, -1 is returned and
- *  errno is set to indicate the error.  Otherwise, return 0.
+ *   If a call to openpty() is not successful, -1 is returned and
+ *   errno is set to indicate the error.  Otherwise, return 0.
  *
  ****************************************************************************/
 
@@ -96,7 +122,7 @@ int openpty(FAR int *master, FAR int *slave, FAR char *name,
 
   /* Open the pseudo terminal master */
 
-  ret = openmaster();
+  ret = posix_openpt(O_RDWR);
   if (ret < 0)
     {
       return ret;