diff --git a/src/cloudabi/mod.rs b/src/cloudabi/mod.rs
index b3065d7237383978f8a722e66db9b09bf9b2b689..71f6ff45ae840173b48436c308797785dad83f7c 100644
--- a/src/cloudabi/mod.rs
+++ b/src/cloudabi/mod.rs
@@ -259,6 +259,7 @@ extern "C" {
     ) -> ::size_t;
 
     pub fn memchr(cx: *const c_void, c: c_int, n: size_t) -> *mut c_void;
+    pub fn wmemchr(cx: *const wchar_t, c: wchar_t, n: size_t) -> *mut wchar_t;
     pub fn memcmp(cx: *const c_void, ct: *const c_void, n: size_t) -> c_int;
     pub fn memcpy(
         dest: *mut c_void,
diff --git a/src/fuchsia/mod.rs b/src/fuchsia/mod.rs
index f5e89573f4d3b36e863f7c276cf7b1b2d55af80c..c4467a8eccf154eb14ddf6dc52d76dfdb11ab4f5 100644
--- a/src/fuchsia/mod.rs
+++ b/src/fuchsia/mod.rs
@@ -3401,6 +3401,7 @@ extern "C" {
     ) -> ::size_t;
 
     pub fn memchr(cx: *const c_void, c: c_int, n: size_t) -> *mut c_void;
+    pub fn wmemchr(cx: *const wchar_t, c: wchar_t, n: size_t) -> *mut wchar_t;
     pub fn memcmp(cx: *const c_void, ct: *const c_void, n: size_t) -> c_int;
     pub fn memcpy(
         dest: *mut c_void,
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index ad0217f2aa8dd750ac34707559fd77a0fe2c92b0..e1e9e499c97af79901aa4d86952561137faa7293 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -546,6 +546,7 @@ extern "C" {
     ) -> ::size_t;
 
     pub fn memchr(cx: *const c_void, c: c_int, n: size_t) -> *mut c_void;
+    pub fn wmemchr(cx: *const wchar_t, c: wchar_t, n: size_t) -> *mut wchar_t;
     pub fn memcmp(cx: *const c_void, ct: *const c_void, n: size_t) -> c_int;
     pub fn memcpy(
         dest: *mut c_void,
diff --git a/src/vxworks/mod.rs b/src/vxworks/mod.rs
index 2df5f0d370a1e02d435c58261c12fec7df67a882..0b90f66b272206f65d1e3ca376d780bdcaa7bbc4 100755
--- a/src/vxworks/mod.rs
+++ b/src/vxworks/mod.rs
@@ -1173,6 +1173,7 @@ extern "C" {
     ) -> ::size_t;
 
     pub fn memchr(cx: *const c_void, c: c_int, n: size_t) -> *mut c_void;
+    pub fn wmemchr(cx: *const wchar_t, c: wchar_t, n: size_t) -> *mut wchar_t;
     pub fn memcmp(cx: *const c_void, ct: *const c_void, n: size_t) -> c_int;
     pub fn memcpy(
         dest: *mut c_void,
diff --git a/src/windows/mod.rs b/src/windows/mod.rs
index f440489aa286d691756c5988c3a80fb49bc81c4b..2fe1d01d78963fe4bfacb7c52838fd4d5ee960d8 100644
--- a/src/windows/mod.rs
+++ b/src/windows/mod.rs
@@ -378,6 +378,7 @@ extern "C" {
     ) -> ::size_t;
 
     pub fn memchr(cx: *const c_void, c: c_int, n: size_t) -> *mut c_void;
+    pub fn wmemchr(cx: *const wchar_t, c: wchar_t, n: size_t) -> *mut wchar_t;
     pub fn memcmp(cx: *const c_void, ct: *const c_void, n: size_t) -> c_int;
     pub fn memcpy(
         dest: *mut c_void,