diff --git a/fs/socket/socket.c b/fs/socket/socket.c
index 6555f4255d177..eb80a9ebc89f7 100644
--- a/fs/socket/socket.c
+++ b/fs/socket/socket.c
@@ -51,6 +51,7 @@ static int sock_file_ioctl(FAR struct file *filep, int cmd,
                            unsigned long arg);
 static int sock_file_poll(FAR struct file *filep, struct pollfd *fds,
                           bool setup);
+static int sock_file_truncate(FAR struct file *filep, off_t length);
 
 /****************************************************************************
  * Private Data
@@ -58,15 +59,15 @@ static int sock_file_poll(FAR struct file *filep, struct pollfd *fds,
 
 static const struct file_operations g_sock_fileops =
 {
-  sock_file_open,   /* open */
-  sock_file_close,  /* close */
-  sock_file_read,   /* read */
-  sock_file_write,  /* write */
-  NULL,             /* seek */
-  sock_file_ioctl,  /* ioctl */
-  NULL,             /* mmap */
-  NULL,             /* truncate */
-  sock_file_poll    /* poll */
+  sock_file_open,     /* open */
+  sock_file_close,    /* close */
+  sock_file_read,     /* read */
+  sock_file_write,    /* write */
+  NULL,               /* seek */
+  sock_file_ioctl,    /* ioctl */
+  NULL,               /* mmap */
+  sock_file_truncate, /* truncate */
+  sock_file_poll      /* poll */
 };
 
 static struct inode g_sock_inode =
@@ -140,6 +141,11 @@ static int sock_file_poll(FAR struct file *filep, FAR struct pollfd *fds,
   return psock_poll(filep->f_priv, fds, setup);
 }
 
+static int sock_file_truncate(FAR struct file *filep, off_t length)
+{
+  return -EINVAL;
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/