libc: Add a very bare-bones locale.h

libc/CMakeLists.txt

@@ -19,6 +19,7 @@ set(SOURCES
     src/env.cpp
     src/pwd.cpp
     src/grp.cpp
+    src/locale.cpp
     src/sys/stat.cpp
     src/sys/mman.cpp
     src/sys/wait.cpp

libc/include/bits/locale-cat.h

@@ -0,0 +1,18 @@
+/* bits/locale-cat.h: Locale categories. */
+
+#ifndef _BITS_LOCALE_CAT_H
+#define _BITS_LOCALE_CAT_H
+
+enum __libc_locale_category
+{
+    LC_ALL,      // Controls all locales.
+    LC_CTYPE,    // Character classification and case conversion.
+    LC_COLLATE,  // Collation order.
+    LC_MONETARY, // Monetary formatting.
+    LC_NUMERIC,  // Numeric, non-monetary formatting.
+    LC_TIME,     // Date and time formats.
+    LC_MESSAGES, // Formats of informative and diagnostic messages and interactive responses.
+    __num_locale_categories,
+};
+
+#endif

libc/include/locale.h

@@ -0,0 +1,20 @@
+/* locale.h: Locale category macros. */
+
+#ifndef _LOCALE_H
+#define _LOCALE_H
+
+#include <bits/locale-cat.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    // Query or set the current locale.
+    char* setlocale(int category, const char* locale);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libc/src/locale.cpp

@@ -0,0 +1,12 @@
+#include <locale.h>
+
+static char s_default_locale[] = "C";
+
+extern "C"
+{
+    char* setlocale(int, const char*)
+    {
+        // FIXME: Set the current locale if <locale> is not NULL.
+        return s_default_locale;
+    }
+}