diff --git a/libc/Makefile b/libc/Makefile
index 1f60bcaf..d8adb659 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -135,6 +135,7 @@ wcschrnul.o \
wcschr.o \
wcscmp.o \
wcscpy.o \
+wcscspn.o \
wcslen.o \
wcsncat.o \
wcsncpy.o \
diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index bdb3f617..5c8e206c 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -68,6 +68,7 @@ wchar_t* wcschr(const wchar_t*, wchar_t);
wchar_t* wcschrnul(const wchar_t*, wchar_t);
int wcscmp(const wchar_t*, const wchar_t*);
wchar_t* wcscpy(wchar_t* restrict, const wchar_t* restrict);
+size_t wcscspn(const wchar_t*, const wchar_t*);
size_t wcslen(const wchar_t*);
wchar_t* wcsncat(wchar_t* restrict, const wchar_t* restrict, size_t);
wchar_t* wcsncpy(wchar_t* restrict, const wchar_t* restrict, size_t);
@@ -105,7 +106,6 @@ long long wcstoll(const wchar_t* restrict, wchar_t** restrict, int);
long wcstol(const wchar_t* restrict, wchar_t** restrict, int);
size_t mbrlen(const char* restrict, size_t, mbstate_t* restrict);
size_t mbsrtowcs(wchar_t* restrict, const char** restrict, size_t, mbstate_t* restrict);
-size_t wcscspn(const wchar_t*, const wchar_t*);
size_t wcsftime(wchar_t* restrict, size_t, const wchar_t* restrict, const struct tm* restrict);
size_t wcsrtombs(char* restrict, const wchar_t** restrict, size_t, mbstate_t* restrict);
size_t wcsxfrm(wchar_t* restrict, const wchar_t* restrict, size_t);
diff --git a/libc/wcscspn.cpp b/libc/wcscspn.cpp
new file mode 100644
index 00000000..86df14b8
--- /dev/null
+++ b/libc/wcscspn.cpp
@@ -0,0 +1,44 @@
+/*******************************************************************************
+
+ Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
+
+ This file is part of the Sortix C Library.
+
+ The Sortix C Library is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or (at your
+ option) any later version.
+
+ The Sortix C Library is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with the Sortix C Library. If not, see .
+
+ wcscspn.cpp
+ Search a string for a set of characters.
+
+*******************************************************************************/
+
+#include
+
+extern "C" size_t wcscspn(const wchar_t* str, const wchar_t* reject)
+{
+ size_t rejectlen = 0;
+ while ( reject[rejectlen] ) { rejectlen++; }
+ for ( size_t result = 0; true; result++ )
+ {
+ wchar_t c = str[result];
+ if ( !c ) { return result; }
+ bool matches = false;
+ for ( size_t i = 0; i < rejectlen; i++ )
+ {
+ if ( str[result] != reject[i] ) { continue; }
+ matches = true;
+ break;
+ }
+ if ( matches ) { return result; }
+ }
+}