diff --git a/Sources/FoundationEssentials/JSON/JSON5Scanner.swift b/Sources/FoundationEssentials/JSON/JSON5Scanner.swift
index 10d1af10b..d0f24d27b 100644
--- a/Sources/FoundationEssentials/JSON/JSON5Scanner.swift
+++ b/Sources/FoundationEssentials/JSON/JSON5Scanner.swift
@@ -1081,7 +1081,7 @@ extension JSON5Scanner {
             jsonBytes.formIndex(after: &index)
         }
 
-        let cmp = jsonBytes[index..<endIndex].prefix(2).withUnsafePointer({ _stringshims_strncasecmp_l($0, "0x", $1, nil) })
+        let cmp = jsonBytes[index..<endIndex].prefix(2).withUnsafePointer({ _stringshims_strncasecmp_clocale($0, "0x", $1) })
         if cmp == 0 {
             jsonBytes.formIndex(&index, offsetBy: 2)
 
diff --git a/Sources/FoundationEssentials/JSON/JSONScanner.swift b/Sources/FoundationEssentials/JSON/JSONScanner.swift
index f78c3637b..5d8668e97 100644
--- a/Sources/FoundationEssentials/JSON/JSONScanner.swift
+++ b/Sources/FoundationEssentials/JSON/JSONScanner.swift
@@ -1179,7 +1179,7 @@ extension Double : PrevalidatedJSONNumberBufferConvertible {
     init?(prevalidatedBuffer buffer: BufferView<UInt8>) {
         let decodedValue = buffer.withUnsafePointer { nptr, count -> Double? in
             var endPtr: UnsafeMutablePointer<CChar>? = nil
-            let decodedValue = _stringshims_strtod_l(nptr, &endPtr, nil)
+            let decodedValue = _stringshims_strtod_clocale(nptr, &endPtr)
             if let endPtr, nptr.advanced(by: count) == endPtr {
                 return decodedValue
             } else {
@@ -1195,7 +1195,7 @@ extension Float : PrevalidatedJSONNumberBufferConvertible {
     init?(prevalidatedBuffer buffer: BufferView<UInt8>) {
         let decodedValue = buffer.withUnsafePointer { nptr, count -> Float? in
             var endPtr: UnsafeMutablePointer<CChar>? = nil
-            let decodedValue = _stringshims_strtof_l(nptr, &endPtr, nil)
+            let decodedValue = _stringshims_strtof_clocale(nptr, &endPtr)
             if let endPtr, nptr.advanced(by: count) == endPtr {
                 return decodedValue
             } else {
diff --git a/Sources/FoundationEssentials/PropertyList/PlistDecoder.swift b/Sources/FoundationEssentials/PropertyList/PlistDecoder.swift
index 79ec14087..3c620cb84 100644
--- a/Sources/FoundationEssentials/PropertyList/PlistDecoder.swift
+++ b/Sources/FoundationEssentials/PropertyList/PlistDecoder.swift
@@ -231,7 +231,7 @@ open class PropertyListDecoder {
         }
         
         return try buffer[unchecked: baseIdx..<idx].withUnsafePointer { ptr, encodingLength in
-            if encodingLength == 5, _stringshims_strncasecmp_l(ptr, "utf-8", 5, nil) == 0 {
+            if encodingLength == 5, _stringshims_strncasecmp_clocale(ptr, "utf-8", 5) == 0 {
                 return .utf8
             }
             
diff --git a/Sources/FoundationEssentials/PropertyList/XMLPlistScanner.swift b/Sources/FoundationEssentials/PropertyList/XMLPlistScanner.swift
index a9d8b407d..e244c463a 100644
--- a/Sources/FoundationEssentials/PropertyList/XMLPlistScanner.swift
+++ b/Sources/FoundationEssentials/PropertyList/XMLPlistScanner.swift
@@ -645,7 +645,7 @@ extension XMLPlistMap.Value {
                     return .nan
                 }
             case (UInt8(ascii: "+"), 9):
-                if _stringshims_strncasecmp_l(buf.baseAddress, "+infinity", 9, nil) == 0 {
+                if _stringshims_strncasecmp_clocale(buf.baseAddress, "+infinity", 9) == 0 {
                     return .infinity
                 }
             case (UInt8(ascii: "+"), 4):
@@ -655,7 +655,7 @@ extension XMLPlistMap.Value {
                     return .infinity
                 }
             case (UInt8(ascii: "-"), 9):
-                if _stringshims_strncasecmp_l(buf.baseAddress, "-infinity", 9, nil) == 0 {
+                if _stringshims_strncasecmp_clocale(buf.baseAddress, "-infinity", 9) == 0 {
                     return .infinity * -1
                 }
             case (UInt8(ascii: "-"), 4):
@@ -665,7 +665,7 @@ extension XMLPlistMap.Value {
                     return .infinity * -1
                 }
             case (UInt8(ascii: "i"), 8), (UInt8(ascii: "I"), 8):
-                if _stringshims_strncasecmp_l(buf.baseAddress, "infinity", 8, nil) == 0 {
+                if _stringshims_strncasecmp_clocale(buf.baseAddress, "infinity", 8) == 0 {
                     return .infinity
                 }
             case (.none, 0):
@@ -728,9 +728,9 @@ extension XMLPlistMap.Value {
                 var parseEndPtr : UnsafeMutablePointer<CChar>?
                 let res : T
                 if MemoryLayout<T>.size == MemoryLayout<Float>.size {
-                    res = T(_stringshims_strtof_l(ptr, &parseEndPtr, nil))
+                    res = T(_stringshims_strtof_clocale(ptr, &parseEndPtr))
                 } else if MemoryLayout<T>.size == MemoryLayout<Double>.size {
-                    res = T(_stringshims_strtod_l(ptr, &parseEndPtr, nil))
+                    res = T(_stringshims_strtod_clocale(ptr, &parseEndPtr))
                 } else {
                     preconditionFailure("Only Float and Double are currently supported by PropertyListDecoder, not \(type))")
                 }
diff --git a/Sources/_FoundationCShims/include/string_shims.h b/Sources/_FoundationCShims/include/string_shims.h
index f6d7ce81a..9d7b586e3 100644
--- a/Sources/_FoundationCShims/include/string_shims.h
+++ b/Sources/_FoundationCShims/include/string_shims.h
@@ -37,11 +37,11 @@ extern "C" {
 #define locale_t void *
 #endif
 
-INTERNAL int _stringshims_strncasecmp_l(const char * _Nullable s1, const char * _Nullable s2, size_t n, locale_t _Nullable loc);
+INTERNAL int _stringshims_strncasecmp_clocale(const char * _Nullable s1, const char * _Nullable s2, size_t n);
 
-INTERNAL double _stringshims_strtod_l(const char * _Nullable __restrict nptr, char * _Nullable * _Nullable __restrict endptr, locale_t _Nullable loc);
+INTERNAL double _stringshims_strtod_clocale(const char * _Nullable __restrict nptr, char * _Nullable * _Nullable __restrict endptr);
 
-INTERNAL float _stringshims_strtof_l(const char * _Nullable __restrict nptr, char * _Nullable * _Nullable __restrict endptr, locale_t _Nullable loc);
+INTERNAL float _stringshims_strtof_clocale(const char * _Nullable __restrict nptr, char * _Nullable * _Nullable __restrict endptr);
 
 #define _STRINGSHIMS_MACROMAN_MAP_SIZE 129
 INTERNAL const uint8_t _stringshims_macroman_mapping[_STRINGSHIMS_MACROMAN_MAP_SIZE][3];
diff --git a/Sources/_FoundationCShims/string_shims.c b/Sources/_FoundationCShims/string_shims.c
index 2a744ab20..877c325be 100644
--- a/Sources/_FoundationCShims/string_shims.c
+++ b/Sources/_FoundationCShims/string_shims.c
@@ -23,57 +23,57 @@
 #include <strings.h>
 #endif
 
-int _stringshims_strncasecmp_l(const char * _Nullable s1,
-                      const char * _Nullable s2,
-                      size_t n,
-                      locale_t _Nullable loc)
-{
 #if TARGET_OS_WINDOWS
-  static _locale_t storage;
-  static _locale_t *cloc = NULL;
-  if (cloc == NULL) {
-    storage = _create_locale(LC_ALL, "C");
-    cloc = &storage;
-  }
-  return _strnicmp_l(s1, s2, n, loc ? loc : *cloc);
-#else
-    if (loc != NULL) {
-#if (defined(TARGET_OS_EXCLAVEKIT) && TARGET_OS_EXCLAVEKIT) || \
-      (defined(TARGET_OS_ANDROID) && TARGET_OS_ANDROID && __ANDROID_API__ < 23)
-        abort();
+#define FOUNDATION_C_LOCALE (_clocale())
+static _locale_t _clocale() {
+    static _locale_t storage;
+    static bool once = false;
+    if (!once) {
+        storage = _create_locale(LC_ALL, "C");
+        once = true;
+    }
+    return storage;
+}
+#elif TARGET_OS_MAC
+#define FOUNDATION_C_LOCALE LC_C_LOCALE
 #else
-        return strncasecmp_l(s1, s2, n, loc);
-#endif
+#define FOUNDATION_C_LOCALE (_clocale())
+static locale_t _clocale() {
+    static locale_t storage;
+    static bool once = false;
+    if (!once) {
+        storage = newlocale(LC_ALL_MASK, "C", (locale_t)0);
+        once = true;
     }
-    // On Darwin, NULL loc means unlocalized compare.
-    // Uses the standard C locale for Linux in this case
-#if (defined(TARGET_OS_EXCLAVEKIT) && TARGET_OS_EXCLAVEKIT) || \
+    return storage;
+}
+#endif
+
+
+int _stringshims_strncasecmp_clocale(const char * _Nullable s1,
+                      const char * _Nullable s2,
+                      size_t n)
+{
+#if TARGET_OS_WINDOWS
+    return _strnicmp_l(s1, s2, n, FOUNDATION_C_LOCALE);
+#elif (defined(TARGET_OS_EXCLAVEKIT) && TARGET_OS_EXCLAVEKIT) || \
       (defined(TARGET_OS_ANDROID) && TARGET_OS_ANDROID && __ANDROID_API__ < 23)
     return strncasecmp(s1, s2, n);
-#elif TARGET_OS_MAC
-    return strncasecmp_l(s1, s2, n, NULL);
 #else
-    locale_t clocale = newlocale(LC_ALL_MASK, "C", (locale_t)0);
-    return strncasecmp_l(s1, s2, n, clocale);
-#endif // TARGET_OS_MAC
-#endif // TARGET_OS_WINDOWS
+    return strncasecmp_l(s1, s2, n, FOUNDATION_C_LOCALE);
+#endif
 }
 
-double _stringshims_strtod_l(const char * _Nullable restrict nptr,
-                 char * _Nullable * _Nullable restrict endptr,
-                 locale_t _Nullable loc)
+double _stringshims_strtod_clocale(const char * _Nullable restrict nptr,
+                 char * _Nullable * _Nullable restrict endptr)
 {
-#if defined(TARGET_OS_EXCLAVEKIT) && TARGET_OS_EXCLAVEKIT
-    assert(loc == NULL);
-    return strtod_l(nptr, endptr, NULL);
-#elif TARGET_OS_MAC
-    return strtod_l(nptr, endptr, loc);
+#if TARGET_OS_MAC
+    return strtod_l(nptr, endptr, FOUNDATION_C_LOCALE);
 #elif TARGET_OS_WINDOWS
-    return _strtod_l(nptr, endptr, loc);
+    return _strtod_l(nptr, endptr, FOUNDATION_C_LOCALE);
 #else
     // Use the C locale
-    locale_t clocale = newlocale(LC_ALL_MASK, "C", (locale_t)0);
-    locale_t oldLocale = uselocale(clocale);
+    locale_t oldLocale = uselocale(FOUNDATION_C_LOCALE);
     double result = strtod(nptr, endptr);
     // Restore locale
     uselocale(oldLocale);
@@ -81,22 +81,17 @@ double _stringshims_strtod_l(const char * _Nullable restrict nptr,
 #endif
 }
 
-float _stringshims_strtof_l(const char * _Nullable restrict nptr,
-                 char * _Nullable * _Nullable restrict endptr,
-                 locale_t _Nullable loc)
+float _stringshims_strtof_clocale(const char * _Nullable restrict nptr,
+                 char * _Nullable * _Nullable restrict endptr)
 {
-#if defined(TARGET_OS_EXCLAVEKIT) && TARGET_OS_EXCLAVEKIT
-    assert(loc == NULL);
-    return strtof_l(nptr, endptr, NULL);
-#elif TARGET_OS_MAC
-    return strtof_l(nptr, endptr, loc);
+#if TARGET_OS_MAC
+    return strtof_l(nptr, endptr, FOUNDATION_C_LOCALE);
 #elif TARGET_OS_WINDOWS
-    return _strtof_l(nptr, endptr, loc);
+    return _strtof_l(nptr, endptr, FOUNDATION_C_LOCALE);
 #else
     // Use the C locale
-    locale_t clocale = newlocale(LC_ALL_MASK, "C", (locale_t)0);
-    locale_t oldLocale = uselocale(clocale);
-    float result = strtof(nptr, endptr);
+    locale_t oldLocale = uselocale(FOUNDATION_C_LOCALE);
+    double result = strtof(nptr, endptr);
     // Restore locale
     uselocale(oldLocale);
     return result;