diff --git a/src/new/vxworks/mod.rs b/src/new/vxworks/mod.rs
index 65630565e53e0..31600129daab0 100644
--- a/src/new/vxworks/mod.rs
+++ b/src/new/vxworks/mod.rs
@@ -1,4 +1,7 @@
 //! VxWorks libc.
+//!
+//! VxWorks allows compiling different types of programs. The `libc` crate only
+//! supports RTPs. Refer to the RTP definitions in case of discrepancy.
 // FIXME(vxworks): link to headers needed.
 
 pub(crate) mod unistd;
diff --git a/src/vxworks/mod.rs b/src/vxworks/mod.rs
index a5f5c6908960c..aab92c65c59a5 100644
--- a/src/vxworks/mod.rs
+++ b/src/vxworks/mod.rs
@@ -58,7 +58,12 @@ pub type pthread_key_t = c_ulong;
 
 // From b_off_t.h
 pub type off_t = c_longlong;
-pub type off64_t = off_t;
+
+#[deprecated(
+    since = "0.2.187",
+    note = "Kernel mode definitions are unsupported. Use `off_t` instead."
+)]
+pub type off64_t = c_longlong;
 
 // From b_BOOL.h
 pub type BOOL = c_int;
@@ -2414,14 +2419,6 @@ safe_f! {
     }
 }
 
-pub unsafe fn pread(_fd: c_int, _buf: *mut c_void, _count: size_t, _offset: off64_t) -> ssize_t {
-    -1
-}
-
-pub unsafe fn pwrite(_fd: c_int, _buf: *const c_void, _count: size_t, _offset: off64_t) -> ssize_t {
-    -1
-}
-
 pub unsafe fn posix_memalign(memptr: *mut *mut c_void, align: size_t, size: size_t) -> c_int {
     // check to see if align is a power of 2 and if align is a multiple
     //  of sizeof(void *)