diff --git a/src/header/inttypes/mod.rs b/src/header/inttypes/mod.rs
index 29eff295dd..2a77afb991 100644
--- a/src/header/inttypes/mod.rs
+++ b/src/header/inttypes/mod.rs
@@ -80,7 +80,7 @@ pub unsafe extern "C" fn wcstoimax(
     base: c_int,
 ) -> intmax_t {
     skipws!(ptr);
-    let result = strto_impl!(intmax_t, ptr, base);
+    let result = wcsto_impl!(intmax_t, ptr, base);
     if !end.is_null() {
         unsafe { *end = ptr.cast_mut() };
     }
@@ -95,7 +95,7 @@ pub unsafe extern "C" fn wcstoumax(
     base: c_int,
 ) -> uintmax_t {
     skipws!(ptr);
-    let result = strtou_impl!(uintmax_t, ptr, base);
+    let result = wcsto_impl!(uintmax_t, ptr, base);
     if !end.is_null() {
         unsafe { *end = ptr.cast_mut() };
     }
diff --git a/src/header/wchar/mod.rs b/src/header/wchar/mod.rs
index 70b17108fe..7f67b64d78 100644
--- a/src/header/wchar/mod.rs
+++ b/src/header/wchar/mod.rs
@@ -855,7 +855,7 @@ pub unsafe extern "C" fn wcstol(
     base: c_int,
 ) -> c_long {
     skipws!(ptr);
-    let result = strto_impl!(c_long, ptr, base);
+    let result = wcsto_impl!(c_long, ptr, base);
     if !end.is_null() {
         unsafe { *end = ptr.cast_mut() };
     }
@@ -870,7 +870,7 @@ pub unsafe extern "C" fn wcstoll(
     base: c_int,
 ) -> c_longlong {
     skipws!(ptr);
-    let result = strto_impl!(c_longlong, ptr, base);
+    let result = wcsto_impl!(c_longlong, ptr, base);
     if !end.is_null() {
         unsafe { *end = ptr.cast_mut() };
     }
@@ -885,7 +885,7 @@ pub unsafe extern "C" fn wcstoul(
     base: c_int,
 ) -> c_ulong {
     skipws!(ptr);
-    let result = strtou_impl!(c_ulong, ptr, base);
+    let result = wcsto_impl!(c_ulong, ptr, base);
     if !end.is_null() {
         unsafe { *end = ptr.cast_mut() };
     }
@@ -900,7 +900,7 @@ pub unsafe extern "C" fn wcstoull(
     base: c_int,
 ) -> c_ulonglong {
     skipws!(ptr);
-    let result = strtou_impl!(c_ulonglong, ptr, base);
+    let result = wcsto_impl!(c_ulonglong, ptr, base);
     if !end.is_null() {
         unsafe { *end = ptr.cast_mut() };
     }
diff --git a/src/macros.rs b/src/macros.rs
index 7ce4ff9505..efe5fef5fe 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -127,11 +127,16 @@ macro_rules! skipws {
 }
 
 #[macro_export]
-macro_rules! strtou_impl {
-    ($type:ident, $ptr:expr, $base:expr) => {
-        strtou_impl!($type, $ptr, $base, false)
-    };
-    ($type:ident, $ptr:expr, $base:expr, $negative:expr) => {{
+macro_rules! wcsto_impl {
+    ($type:ident, $ptr:expr, $base:expr) => {{
+        let has_minus = unsafe { *$ptr } == '-' as wchar_t;
+        let has_plus = unsafe { *$ptr } == '+' as wchar_t;
+        if has_minus || has_plus {
+            $ptr = unsafe { $ptr.add(1) };
+        }
+
+        let type_is_signed = $type::MIN != 0;
+
         let mut base = $base;
 
         if (base == 16 || base == 0)
@@ -156,7 +161,7 @@ macro_rules! strtou_impl {
             char::from_u32(unsafe { *$ptr } as u32).and_then(|c| c.to_digit(base as u32))
         {
             let new = result.checked_mul(base as $type).and_then(|result| {
-                if $negative {
+                if has_minus && type_is_signed {
                     #[cfg(target_arch = "x86")]
                     {
                         result.checked_sub(
@@ -190,6 +195,9 @@ macro_rules! strtou_impl {
 
             $ptr = unsafe { $ptr.add(1) };
         }
+        if has_minus && !type_is_signed {
+            result = $type::MAX - result + 1;
+        }
         result
     }};
 }
@@ -297,14 +305,6 @@ macro_rules! strto_impl {
 
         num
     }};
-    // this variant is used by wchar (also wcstoimax and wcstoumax from inttypes)
-    ($type:ident, $ptr:expr, $base:expr) => {{
-        let negative = unsafe { *$ptr } == '-' as wchar_t;
-        if negative {
-            $ptr = unsafe { $ptr.add(1) };
-        }
-        strtou_impl!($type, $ptr, $base, negative)
-    }};
 }
 
 #[macro_export]