diff --git a/docs/status.md b/docs/status.md
index d509e41..ddcb728 100644
--- a/docs/status.md
+++ b/docs/status.md
@@ -55,7 +55,9 @@
   * `close_range` and `copy_file_range` (Linux-specific GNU extensions).
 
 New libc behavior in U (API level 34):
-  * Support for `%b` and `%B` in the printf and wprintf family.
+  * Support for `%b` and `%B` in the printf/wprintf family, `%b` in the
+    scanf/wscanf family, and `0b` prefixes with base 0 in the strtol/wcstol
+    family.
 
 New libc functions in T (API level 33):
   * `backtrace`, `backtrace_symbols`, `backtrace_symbols_fd` (`<execinfo.h>`).
diff --git a/libc/Android.bp b/libc/Android.bp
index b7cb59d..f064047 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -35,7 +35,7 @@
     "stdio/stdio.cpp",
     "stdio/stdio_ext.cpp",
     "stdio/vfscanf.cpp",
-    "stdio/vfwscanf.c",
+    "stdio/vfwscanf.cpp",
 ]
 
 // off64_t/time64_t support on LP32.
@@ -500,13 +500,7 @@
         "upstream-openbsd/lib/libc/locale/mbstowcs.c",
         "upstream-openbsd/lib/libc/locale/mbtowc.c",
         "upstream-openbsd/lib/libc/locale/wcscoll.c",
-        "upstream-openbsd/lib/libc/locale/wcstoimax.c",
-        "upstream-openbsd/lib/libc/locale/wcstol.c",
-        "upstream-openbsd/lib/libc/locale/wcstoll.c",
         "upstream-openbsd/lib/libc/locale/wcstombs.c",
-        "upstream-openbsd/lib/libc/locale/wcstoul.c",
-        "upstream-openbsd/lib/libc/locale/wcstoull.c",
-        "upstream-openbsd/lib/libc/locale/wcstoumax.c",
         "upstream-openbsd/lib/libc/locale/wcsxfrm.c",
         "upstream-openbsd/lib/libc/locale/wctob.c",
         "upstream-openbsd/lib/libc/locale/wctomb.c",
diff --git a/libc/bionic/strtol.cpp b/libc/bionic/strtol.cpp
index 77f1d92..ec72b09 100644
--- a/libc/bionic/strtol.cpp
+++ b/libc/bionic/strtol.cpp
@@ -32,11 +32,13 @@
 #include <inttypes.h>
 #include <limits.h>
 #include <stdlib.h>
+#include <wchar.h>
 
-template <typename T, T Min, T Max> T StrToI(const char* nptr, char** endptr, int base) {
+template <typename T, T Min, T Max, typename CharT>
+T StrToI(const CharT* nptr, CharT** endptr, int base) {
   // Ensure that base is between 2 and 36 inclusive, or the special value of 0.
   if (base < 0 || base == 1 || base > 36) {
-    if (endptr != nullptr) *endptr = const_cast<char*>(nptr);
+    if (endptr != nullptr) *endptr = const_cast<CharT*>(nptr);
     errno = EINVAL;
     return 0;
   }
@@ -44,7 +46,7 @@
   // Skip white space and pick up leading +/- sign if any.
   // If base is 0, allow 0x for hex and 0 for octal, else
   // assume decimal; if base is already 16, allow 0x.
-  const char* s = nptr;
+  const CharT* s = nptr;
   int c;
   do {
     c = *s++;
@@ -62,6 +64,11 @@
     s += 2;
     base = 16;
   }
+  if ((base == 0 || base == 2) && c == '0' && (*s == 'b' || *s == 'B') && isdigit(s[1])) {
+    c = s[1];
+    s += 2;
+    base = 2;
+  }
   if (base == 0) base = (c == '0') ? 8 : 10;
 
   // We always work in the negative space because the most negative value has a
@@ -91,7 +98,7 @@
       acc -= c;
     }
   }
-  if (endptr != nullptr) *endptr = const_cast<char*>(any ? s - 1 : nptr);
+  if (endptr != nullptr) *endptr = const_cast<CharT*>(any ? s - 1 : nptr);
   if (!neg) {
     if (acc == Min) {
       errno = ERANGE;
@@ -103,14 +110,15 @@
   return acc;
 }
 
-template <typename T, T Max> T StrToU(const char* nptr, char** endptr, int base) {
+template <typename T, T Max, typename CharT>
+T StrToU(const CharT* nptr, CharT** endptr, int base) {
   if (base < 0 || base == 1 || base > 36) {
-    if (endptr != nullptr) *endptr = const_cast<char*>(nptr);
+    if (endptr != nullptr) *endptr = const_cast<CharT*>(nptr);
     errno = EINVAL;
     return 0;
   }
 
-  const char* s = nptr;
+  const CharT* s = nptr;
   int c;
   do {
     c = *s++;
@@ -128,6 +136,11 @@
     s += 2;
     base = 16;
   }
+  if ((base == 0 || base == 2) && c == '0' && (*s == 'b' || *s == 'B') && isdigit(s[1])) {
+    c = s[1];
+    s += 2;
+    base = 2;
+  }
   if (base == 0) base = (c == '0') ? 8 : 10;
 
   T cutoff = Max / static_cast<T>(base);
@@ -155,7 +168,7 @@
     }
   }
   if (neg && any > 0) acc = -acc;
-  if (endptr != nullptr) *endptr = const_cast<char*>(any ? s - 1 : nptr);
+  if (endptr != nullptr) *endptr = const_cast<CharT*>(any ? s - 1 : nptr);
   return acc;
 }
 
@@ -172,30 +185,54 @@
 }
 
 intmax_t strtoimax(const char* s, char** end, int base) {
-  return StrToI<intmax_t, INTMAX_MIN, INTMAX_MAX>(s, end, base);
+  return StrToI<intmax_t, INTMAX_MIN, INTMAX_MAX, char>(s, end, base);
+}
+
+intmax_t wcstoimax(const wchar_t* s, wchar_t** end, int base) {
+  return StrToI<intmax_t, INTMAX_MIN, INTMAX_MAX, wchar_t>(s, end, base);
 }
 
 long strtol(const char* s, char** end, int base) {
-  return StrToI<long, LONG_MIN, LONG_MAX>(s, end, base);
+  return StrToI<long, LONG_MIN, LONG_MAX, char>(s, end, base);
+}
+
+long wcstol(const wchar_t* s, wchar_t** end, int base) {
+  return StrToI<long, LONG_MIN, LONG_MAX, wchar_t>(s, end, base);
 }
 
 long long strtoll(const char* s, char** end, int base) {
-  return StrToI<long long, LLONG_MIN, LLONG_MAX>(s, end, base);
+  return StrToI<long long, LLONG_MIN, LLONG_MAX, char>(s, end, base);
+}
+
+long long wcstoll(const wchar_t* s, wchar_t** end, int base) {
+  return StrToI<long long, LLONG_MIN, LLONG_MAX, wchar_t>(s, end, base);
 }
 
 // Public API since L, but not in any header.
 __strong_alias(strtoq, strtoll);
 
 unsigned long strtoul(const char* s, char** end, int base) {
-  return StrToU<unsigned long, ULONG_MAX>(s, end, base);
+  return StrToU<unsigned long, ULONG_MAX, char>(s, end, base);
+}
+
+unsigned long wcstoul(const wchar_t* s, wchar_t** end, int base) {
+  return StrToU<unsigned long, ULONG_MAX, wchar_t>(s, end, base);
 }
 
 unsigned long long strtoull(const char* s, char** end, int base) {
-  return StrToU<unsigned long long, ULLONG_MAX>(s, end, base);
+  return StrToU<unsigned long long, ULLONG_MAX, char>(s, end, base);
+}
+
+unsigned long long wcstoull(const wchar_t* s, wchar_t** end, int base) {
+  return StrToU<unsigned long long, ULLONG_MAX, wchar_t>(s, end, base);
 }
 
 uintmax_t strtoumax(const char* s, char** end, int base) {
-  return StrToU<uintmax_t, UINTMAX_MAX>(s, end, base);
+  return StrToU<uintmax_t, UINTMAX_MAX, char>(s, end, base);
+}
+
+uintmax_t wcstoumax(const wchar_t* s, wchar_t** end, int base) {
+  return StrToU<uintmax_t, UINTMAX_MAX, wchar_t>(s, end, base);
 }
 
 // Public API since L, but not in any header.
diff --git a/libc/stdio/vfscanf.cpp b/libc/stdio/vfscanf.cpp
index 424c4ef..d05a3a6 100644
--- a/libc/stdio/vfscanf.cpp
+++ b/libc/stdio/vfscanf.cpp
@@ -69,7 +69,8 @@
 #define HAVESIGN   0x04000 // Sign detected
 #define NDIGITS    0x08000 // No digits detected
 #define PFXOK      0x10000 // "0x" prefix is (still) legal
-#define NZDIGITS   0x20000 // No zero digits detected
+#define PFBOK      0x20000 // "0b" prefix is (still) legal
+#define NZDIGITS   0x40000 // No zero digits detected
 
 // Conversion types.
 #define CT_CHAR 0   // %c conversion
@@ -101,9 +102,6 @@
   void* allocation = nullptr; // Allocated but unassigned result for %mc/%ms/%m[.
   size_t capacity = 0; // Number of char/wchar_t units allocated in `allocation`.
 
-  /* `basefix' is used to avoid `if' tests in the integer scanner */
-  static short basefix[17] = { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
-
   _SET_ORIENTATION(fp, -1);
 
   nassigned = 0;
@@ -188,6 +186,12 @@
        * Conversions.
        * Those marked `compat' are for 4.[123]BSD compatibility.
        */
+      case 'b':
+        c = CT_INT;
+        base = 2;
+        flags |= PFBOK; /* enable 0b prefixing */
+        break;
+
       case 'D': /* compat */
         flags |= LONG;
         __BIONIC_FALLTHROUGH;
@@ -558,7 +562,7 @@
              * digits (zero or nonzero) have been
              * scanned (only signs), we will have
              * base==0.  In that case, we should set
-             * it to 8 and enable 0x prefixing.
+             * it to 8 and enable 0b/0x prefixing.
              * Also, if we have not scanned zero digits
              * before this, do not turn off prefixing
              * (someone else will turn it off if we
@@ -567,15 +571,24 @@
             case '0':
               if (base == 0) {
                 base = 8;
-                flags |= PFXOK;
+                flags |= PFBOK | PFXOK;
               }
-              if (flags & NZDIGITS)
+              if (flags & NZDIGITS) {
                 flags &= ~(SIGNOK | NZDIGITS | NDIGITS);
-              else
-                flags &= ~(SIGNOK | PFXOK | NDIGITS);
+              } else {
+                flags &= ~(SIGNOK | PFBOK | PFXOK | NDIGITS);
+              }
               goto ok;
-
-            /* 1 through 7 always legal */
+            case 'B':
+            case 'b':
+              // Is this 'b' or 'B' potentially part of an "0b" prefix?
+              if ((flags & PFBOK) && p == buf + 1 + !!(flags & HAVESIGN)) {
+                base = 2;
+                flags &= ~PFBOK;
+                goto ok;
+              }
+              // No? Fall through and see if it's a hex digit instead then...
+              __BIONIC_FALLTHROUGH;
             case '1':
             case '2':
             case '3':
@@ -583,34 +596,21 @@
             case '5':
             case '6':
             case '7':
-              base = basefix[base];
-              flags &= ~(SIGNOK | PFXOK | NDIGITS);
-              goto ok;
-
-            /* digits 8 and 9 ok iff decimal or hex */
             case '8':
             case '9':
-              base = basefix[base];
-              if (base <= 8) break; /* not legal here */
-              flags &= ~(SIGNOK | PFXOK | NDIGITS);
-              goto ok;
-
-            /* letters ok iff hex */
             case 'A':
-            case 'B':
             case 'C':
             case 'D':
             case 'E':
             case 'F':
             case 'a':
-            case 'b':
             case 'c':
             case 'd':
             case 'e':
             case 'f':
-              /* no need to fix base here */
-              if (base <= 10) break; /* not legal here */
-              flags &= ~(SIGNOK | PFXOK | NDIGITS);
+              if (base == 0) base = 10;
+              if (base != 16 && (c - '0') >= base) break; /* not legal here */
+              flags &= ~(SIGNOK | PFBOK | PFXOK | NDIGITS);
               goto ok;
 
             /* sign ok only as first character */
@@ -653,17 +653,16 @@
             break; /* EOF */
         }
         /*
-         * If we had only a sign, it is no good; push
-         * back the sign.  If the number ends in `x',
-         * it was [sign] '0' 'x', so push back the x
-         * and treat it as [sign] '0'.
+         * If we had only a sign, it is no good; push back the sign.
+         * If the number was `[-+]0[BbXx]`, push back and treat it
+         * as `[-+]0`.
          */
         if (flags & NDIGITS) {
           if (p > buf) (void)ungetc(*(u_char*)--p, fp);
           goto match_failure;
         }
         c = ((u_char*)p)[-1];
-        if (c == 'x' || c == 'X') {
+        if ((base == 2 && (c == 'b' || c == 'B')) || c == 'x' || c == 'X') {
           --p;
           (void)ungetc(c, fp);
         }
diff --git a/libc/stdio/vfwscanf.c b/libc/stdio/vfwscanf.cpp
similarity index 91%
rename from libc/stdio/vfwscanf.c
rename to libc/stdio/vfwscanf.cpp
index 71cd49b..06f706a 100644
--- a/libc/stdio/vfwscanf.c
+++ b/libc/stdio/vfwscanf.cpp
@@ -42,6 +42,8 @@
 #include <wctype.h>
 #include "local.h"
 
+#include <platform/bionic/macros.h>
+
 #define BUF 513 /* Maximum length of numeric string. */
 
 /*
@@ -65,15 +67,16 @@
  * SIGNOK, HAVESIGN, NDIGITS, DPTOK, and EXPOK are for floating point;
  * SIGNOK, HAVESIGN, NDIGITS, PFXOK, and NZDIGITS are for integral.
  */
-#define SIGNOK 0x01000   /* +/- is (still) legal */
+#define SIGNOK   0x01000  /* +/- is (still) legal */
 #define HAVESIGN 0x02000 /* sign detected */
-#define NDIGITS 0x04000  /* no digits detected */
+#define NDIGITS  0x04000 /* no digits detected */
 
-#define DPTOK 0x08000 /* (float) decimal point is still legal */
-#define EXPOK 0x10000 /* (float) exponent (e+3, etc) still legal */
+#define DPTOK    0x08000 /* (float) decimal point is still legal */
+#define EXPOK    0x10000 /* (float) exponent (e+3, etc) still legal */
 
-#define PFXOK 0x08000    /* 0x prefix is (still) legal */
-#define NZDIGITS 0x10000 /* no zero digits detected */
+#define PFBOK    0x20000 /* 0x prefix is (still) legal */
+#define PFXOK    0x40000 /* 0x prefix is (still) legal */
+#define NZDIGITS 0x80000 /* no zero digits detected */
 
 /*
  * Conversion types.
@@ -147,9 +150,6 @@
   char mbbuf[MB_LEN_MAX]; /* temporary mb. character buffer */
   mbstate_t mbs;
 
-  /* `basefix' is used to avoid `if' tests in the integer scanner */
-  static short basefix[17] = { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
-
   _SET_ORIENTATION(fp, 1);
 
   nassigned = 0;
@@ -239,9 +239,15 @@
        * Conversions.
        * Those marked `compat' are for 4.[123]BSD compatibility.
        */
+      case 'b':
+        c = CT_INT;
+        base = 2;
+        flags |= PFBOK; /* enable 0b prefixing */
+        break;
+
       case 'D': /* compat */
         flags |= LONG;
-        /* FALLTHROUGH */
+        __BIONIC_FALLTHROUGH;
       case 'd':
         c = CT_INT;
         base = 10;
@@ -254,7 +260,7 @@
 
       case 'O': /* compat */
         flags |= LONG;
-        /* FALLTHROUGH */
+        __BIONIC_FALLTHROUGH;
       case 'o':
         c = CT_INT;
         flags |= UNSIGNED;
@@ -468,7 +474,7 @@
              * digits (zero or nonzero) have been
              * scanned (only signs), we will have
              * base==0.  In that case, we should set
-             * it to 8 and enable 0x prefixing.
+             * it to 8 and enable 0b/0x prefixing.
              * Also, if we have not scanned zero digits
              * before this, do not turn off prefixing
              * (someone else will turn it off if we
@@ -477,15 +483,26 @@
             case '0':
               if (base == 0) {
                 base = 8;
-                flags |= PFXOK;
+                flags |= PFBOK | PFXOK;
               }
-              if (flags & NZDIGITS)
+              if (flags & NZDIGITS) {
                 flags &= ~(SIGNOK | NZDIGITS | NDIGITS);
-              else
-                flags &= ~(SIGNOK | PFXOK | NDIGITS);
+              } else {
+                flags &= ~(SIGNOK | PFBOK | PFXOK | NDIGITS);
+              }
               goto ok;
 
             /* 1 through 7 always legal */
+            case 'B':
+            case 'b':
+              // Is this 'b' potentially part of an "0b" prefix?
+              if ((flags & PFBOK) && p == buf + 1 + !!(flags & HAVESIGN)) {
+                base = 2;
+                flags &= ~PFBOK;
+                goto ok;
+              }
+              // No? Fall through and see if it's a hex digit instead then...
+              __BIONIC_FALLTHROUGH;
             case '1':
             case '2':
             case '3':
@@ -493,34 +510,21 @@
             case '5':
             case '6':
             case '7':
-              base = basefix[base];
-              flags &= ~(SIGNOK | PFXOK | NDIGITS);
-              goto ok;
-
-            /* digits 8 and 9 ok iff decimal or hex */
             case '8':
             case '9':
-              base = basefix[base];
-              if (base <= 8) break; /* not legal here */
-              flags &= ~(SIGNOK | PFXOK | NDIGITS);
-              goto ok;
-
-            /* letters ok iff hex */
             case 'A':
-            case 'B':
             case 'C':
             case 'D':
             case 'E':
             case 'F':
             case 'a':
-            case 'b':
             case 'c':
             case 'd':
             case 'e':
             case 'f':
-              /* no need to fix base here */
-              if (base <= 10) break; /* not legal here */
-              flags &= ~(SIGNOK | PFXOK | NDIGITS);
+              if (base == 0) base = 10;
+              if (base != 16 && (int)(c - '0') >= base) break; /* not legal here */
+              flags &= ~(SIGNOK | PFBOK | PFXOK | NDIGITS);
               goto ok;
 
             /* sign ok only as first character */
@@ -560,17 +564,16 @@
           *p++ = (wchar_t)c;
         }
         /*
-         * If we had only a sign, it is no good; push
-         * back the sign.  If the number ends in `x',
-         * it was [sign] '0' 'x', so push back the x
-         * and treat it as [sign] '0'.
+         * If we had only a sign, it is no good; push back the sign.
+         * If the number was `[-+]0[BbXx]`, push back and treat it
+         * as `[-+]0`.
          */
         if (flags & NDIGITS) {
           if (p > buf) __ungetwc(*--p, fp);
           goto match_failure;
         }
         c = p[-1];
-        if (c == 'x' || c == 'X') {
+        if ((base == 2 && (c == 'b' || c == 'B')) || c == 'x' || c == 'X') {
           --p;
           __ungetwc(c, fp);
         }
diff --git a/libc/upstream-openbsd/lib/libc/locale/_wcstol.h b/libc/upstream-openbsd/lib/libc/locale/_wcstol.h
deleted file mode 100644
index 1b60a3a..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/_wcstol.h
+++ /dev/null
@@ -1,136 +0,0 @@
-/*	$OpenBSD: _wcstol.h,v 1.3 2015/10/01 02:32:07 guenther Exp $	*/
-/* $NetBSD: _wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp $ */
-
-/*-
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * Original version ID:
- * @(#)strtol.c	8.1 (Berkeley) 6/4/93
- * NetBSD: wcstol.c,v 1.1 2001/09/27 16:30:36 yamt Exp
- * Citrus: xpg4dl/FreeBSD/lib/libc/locale/wcstol.c,v 1.2 2001/09/21 16:11:41 yamt Exp
- */
-
-/*
- * function template for wcstol, wcstoll and wcstoimax.
- *
- * parameters:
- *	FUNCNAME : function name
- *      int_type : return type
- *      MIN_VALUE : lower limit of the return type
- *      MAX_VALUE : upper limit of the return type
- */
-
-int_type
-FUNCNAME(const wchar_t *nptr, wchar_t **endptr, int base)
-{
-	const wchar_t *s;
-	int_type acc, cutoff;
-	wint_t wc;
-	int i;
-	int neg, any, cutlim;
-
-	/* check base value */
-	if (base && (base < 2 || base > 36)) {
-		errno = EINVAL;
-		return 0;
-	}
-
-	/*
-	 * Skip white space and pick up leading +/- sign if any.
-	 * If base is 0, allow 0x for hex and 0 for octal, else
-	 * assume decimal; if base is already 16, allow 0x.
-	 */
-	s = nptr;
-	do {
-		wc = (wchar_t) *s++;
-	} while (iswspace(wc));
-	if (wc == L'-') {
-		neg = 1;
-		wc = *s++;
-	} else {
-		neg = 0;
-		if (wc == L'+')
-			wc = *s++;
-	}
-	if ((base == 0 || base == 16) &&
-	    wc == L'0' && (*s == L'x' || *s == L'X')) {
-		wc = s[1];
-		s += 2;
-		base = 16;
-	}
-	if (base == 0)
-		base = wc == L'0' ? 8 : 10;
-
-	/*
-	 * See strtol for comments as to the logic used.
-	 */
-	cutoff = neg ? MIN_VALUE : MAX_VALUE;
-	cutlim = (int)(cutoff % base);
-	cutoff /= base;
-	if (neg) {
-		if (cutlim > 0) {
-			cutlim -= base;
-			cutoff += 1;
-		}
-		cutlim = -cutlim;
-	}
-	for (acc = 0, any = 0;; wc = (wchar_t) *s++) {
-		i = wctoint(wc);
-		if (i == -1)
-			break;
-		if (i >= base)
-			break;
-		if (any < 0)
-			continue;
-		if (neg) {
-			if (acc < cutoff || (acc == cutoff && i > cutlim)) {
-				any = -1;
-				acc = MIN_VALUE;
-				errno = ERANGE;
-			} else {
-				any = 1;
-				acc *= base;
-				acc -= i;
-			}
-		} else {
-			if (acc > cutoff || (acc == cutoff && i > cutlim)) {
-				any = -1;
-				acc = MAX_VALUE;
-				errno = ERANGE;
-			} else {
-				any = 1;
-				acc *= base;
-				acc += i;
-			}
-		}
-	}
-	if (endptr != 0)
-		*endptr = (wchar_t *)(any ? s - 1 : nptr);
-	return (acc);
-}
-DEF_STRONG(FUNCNAME);
diff --git a/libc/upstream-openbsd/lib/libc/locale/_wcstoul.h b/libc/upstream-openbsd/lib/libc/locale/_wcstoul.h
deleted file mode 100644
index 159b22b..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/_wcstoul.h
+++ /dev/null
@@ -1,116 +0,0 @@
-/*	$OpenBSD: _wcstoul.h,v 1.3 2015/10/01 02:32:07 guenther Exp $	*/
-/* $NetBSD: _wcstoul.h,v 1.2 2003/08/07 16:43:03 agc Exp $ */
-
-/*
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * Original version ID:
- * @(#)strtoul.c	8.1 (Berkeley) 6/4/93
- * Citrus: xpg4dl/FreeBSD/lib/libc/locale/wcstoul.c,v 1.2 2001/09/21 16:11:41 yamt Exp
- * NetBSD: wcstoul.c,v 1.1 2001/09/27 16:30:37 yamt Exp
- */
-
-/*
- * function template for wcstoul, wcstoull and wcstoumax.
- *
- * parameters:
- *	FUNCNAME  : function name
- *      uint_type : return type
- *      MAX_VALUE : upper limit of the return type
- */
-
-uint_type
-FUNCNAME(const wchar_t *nptr, wchar_t **endptr, int base)
-{
-	const wchar_t *s;
-	uint_type acc, cutoff;
-	wint_t wc;
-	int i;
-	int neg, any, cutlim;
-
-	if (base && (base < 2 || base > 36)) {
-		errno = EINVAL;
-		return 0;
-	}
-
-	/*
-	 * Skip white space and pick up leading +/- sign if any.
-	 * If base is 0, allow 0x for hex and 0 for octal, else
-	 * assume decimal; if base is already 16, allow 0x.
-	 */
-	s = nptr;
-	do {
-		wc = (wchar_t) *s++;
-	} while (iswspace(wc));
-	if (wc == L'-') {
-		neg = 1;
-		wc = *s++;
-	} else {
-		neg = 0;
-		if (wc == L'+')
-			wc = *s++;
-	}
-	if ((base == 0 || base == 16) &&
-	    wc == L'0' && (*s == L'x' || *s == L'X')) {
-		wc = s[1];
-		s += 2;
-		base = 16;
-	}
-	if (base == 0)
-		base = wc == L'0' ? 8 : 10;
-
-	/*
-	 * See strtoul for comments as to the logic used.
-	 */
-	cutoff = MAX_VALUE / (uint_type)base;
-	cutlim = (int)(MAX_VALUE % (uint_type)base);
-	for (acc = 0, any = 0;; wc = (wchar_t) *s++) {
-		i = wctoint(wc);
-		if (i == (wint_t)-1)
-			break;
-		if (i >= base)
-			break;
-		if (any < 0)
-			continue;
-		if (acc > cutoff || (acc == cutoff && i > cutlim)) {
-			any = -1;
-			acc = MAX_VALUE;
-			errno = ERANGE;
-		} else {
-			any = 1;
-			acc *= (uint_type)base;
-			acc += i;
-		}
-	}
-	if (neg && any > 0)
-		acc = -acc;
-	if (endptr != 0)
-		*endptr = (wchar_t *)(any ? s - 1 : nptr);
-	return (acc);
-}
-DEF_STRONG(FUNCNAME);
diff --git a/libc/upstream-openbsd/lib/libc/locale/wcstoimax.c b/libc/upstream-openbsd/lib/libc/locale/wcstoimax.c
deleted file mode 100644
index d46a7c7..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wcstoimax.c
+++ /dev/null
@@ -1,19 +0,0 @@
-/*	$OpenBSD: wcstoimax.c,v 1.1 2009/01/13 18:13:51 kettenis Exp $	*/
-/* $NetBSD: wcstol.c,v 1.2 2003/03/11 09:21:23 tshiozak Exp $ */
-
-#include <ctype.h>
-#include <errno.h>
-#include <inttypes.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
-
-#include "wctoint.h"
-
-#define	FUNCNAME	wcstoimax
-typedef intmax_t	int_type;
-#define	MIN_VALUE	INTMAX_MIN
-#define	MAX_VALUE	INTMAX_MAX
-
-#include "_wcstol.h"
diff --git a/libc/upstream-openbsd/lib/libc/locale/wcstol.c b/libc/upstream-openbsd/lib/libc/locale/wcstol.c
deleted file mode 100644
index 03395a0..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wcstol.c
+++ /dev/null
@@ -1,18 +0,0 @@
-/*	$OpenBSD: wcstol.c,v 1.2 2005/08/08 08:05:35 espie Exp $	*/
-/* $NetBSD: wcstol.c,v 1.2 2003/03/11 09:21:23 tshiozak Exp $ */
-
-#include <ctype.h>
-#include <errno.h>
-#include <limits.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
-
-#include "wctoint.h"
-
-#define	FUNCNAME	wcstol
-typedef long int_type;
-#define	MIN_VALUE	LONG_MIN
-#define	MAX_VALUE	LONG_MAX
-
-#include "_wcstol.h"
diff --git a/libc/upstream-openbsd/lib/libc/locale/wcstoll.c b/libc/upstream-openbsd/lib/libc/locale/wcstoll.c
deleted file mode 100644
index 926db70..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wcstoll.c
+++ /dev/null
@@ -1,18 +0,0 @@
-/*	$OpenBSD: wcstoll.c,v 1.2 2005/08/08 08:05:35 espie Exp $	*/
-/* $NetBSD: wcstoll.c,v 1.1 2003/03/11 09:21:23 tshiozak Exp $ */
-
-#include <ctype.h>
-#include <errno.h>
-#include <limits.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
-
-#include "wctoint.h"
-
-#define	FUNCNAME	wcstoll
-typedef long long int int_type;
-#define	MIN_VALUE	LLONG_MIN
-#define	MAX_VALUE	LLONG_MAX
-
-#include "_wcstol.h"
diff --git a/libc/upstream-openbsd/lib/libc/locale/wcstoul.c b/libc/upstream-openbsd/lib/libc/locale/wcstoul.c
deleted file mode 100644
index e863862..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wcstoul.c
+++ /dev/null
@@ -1,17 +0,0 @@
-/*	$OpenBSD: wcstoul.c,v 1.2 2005/08/08 08:05:35 espie Exp $	*/
-/*	$NetBSD: wcstoul.c,v 1.2 2003/03/11 09:21:24 tshiozak Exp $	*/
-
-#include <ctype.h>
-#include <errno.h>
-#include <limits.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
-
-#include "wctoint.h"
-
-#define	FUNCNAME	wcstoul
-typedef unsigned long uint_type;
-#define	MAX_VALUE	ULONG_MAX
-
-#include "_wcstoul.h"
diff --git a/libc/upstream-openbsd/lib/libc/locale/wcstoull.c b/libc/upstream-openbsd/lib/libc/locale/wcstoull.c
deleted file mode 100644
index 6671c37..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wcstoull.c
+++ /dev/null
@@ -1,17 +0,0 @@
-/*	$OpenBSD: wcstoull.c,v 1.2 2005/08/08 08:05:35 espie Exp $	*/
-/*	$NetBSD: wcstoull.c,v 1.1 2003/03/11 09:21:24 tshiozak Exp $	*/
-
-#include <ctype.h>
-#include <errno.h>
-#include <limits.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
-
-#include "wctoint.h"
-
-#define	FUNCNAME	wcstoull
-typedef unsigned long long int uint_type;
-#define	MAX_VALUE	ULLONG_MAX
-
-#include "_wcstoul.h"
diff --git a/libc/upstream-openbsd/lib/libc/locale/wcstoumax.c b/libc/upstream-openbsd/lib/libc/locale/wcstoumax.c
deleted file mode 100644
index ccd4713..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wcstoumax.c
+++ /dev/null
@@ -1,18 +0,0 @@
-/*	$OpenBSD: wcstoumax.c,v 1.1 2009/01/13 18:13:51 kettenis Exp $	*/
-/*	$NetBSD: wcstoul.c,v 1.2 2003/03/11 09:21:24 tshiozak Exp $	*/
-
-#include <ctype.h>
-#include <errno.h>
-#include <inttypes.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
-
-#include "wctoint.h"
-
-#define	FUNCNAME	wcstoumax
-typedef uintmax_t	uint_type;
-#define	MAX_VALUE	UINTMAX_MAX
-
-#include "_wcstoul.h"
diff --git a/libc/upstream-openbsd/lib/libc/locale/wctoint.h b/libc/upstream-openbsd/lib/libc/locale/wctoint.h
deleted file mode 100644
index ea50c5a..0000000
--- a/libc/upstream-openbsd/lib/libc/locale/wctoint.h
+++ /dev/null
@@ -1,79 +0,0 @@
-/*	$OpenBSD: wctoint.h,v 1.2 2015/09/13 11:38:08 guenther Exp $	*/
-/* $NetBSD: __wctoint.h,v 1.1 2001/09/28 11:25:37 yamt Exp $ */
-
-/*-
- * Copyright (c)2001 Citrus Project,
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	$Citrus: xpg4dl/FreeBSD/lib/libc/locale/__wctoint.h,v 1.1 2001/09/21 13:52:32 yamt Exp $
- */
-
-
-inline static int
-wctoint(wchar_t wc)
-{
-	int n;
-
-	switch (wc) {
-	case L'0': n = 0; break;
-	case L'1': n = 1; break;
-	case L'2': n = 2; break;
-	case L'3': n = 3; break;
-	case L'4': n = 4; break;
-	case L'5': n = 5; break;
-	case L'6': n = 6; break;
-	case L'7': n = 7; break;
-	case L'8': n = 8; break;
-	case L'9': n = 9; break;
-	case L'A': case L'a': n = 10; break;
-	case L'B': case L'b': n = 11; break;
-	case L'C': case L'c': n = 12; break;
-	case L'D': case L'd': n = 13; break;
-	case L'E': case L'e': n = 14; break;
-	case L'F': case L'f': n = 15; break;
-	case L'G': case L'g': n = 16; break;
-	case L'H': case L'h': n = 17; break;
-	case L'I': case L'i': n = 18; break;
-	case L'J': case L'j': n = 19; break;
-	case L'K': case L'k': n = 20; break;
-	case L'L': case L'l': n = 21; break;
-	case L'M': case L'm': n = 22; break;
-	case L'N': case L'n': n = 23; break;
-	case L'O': case L'o': n = 24; break;
-	case L'P': case L'p': n = 25; break;
-	case L'Q': case L'q': n = 26; break;
-	case L'R': case L'r': n = 27; break;
-	case L'S': case L's': n = 28; break;
-	case L'T': case L't': n = 29; break;
-	case L'U': case L'u': n = 30; break;
-	case L'V': case L'v': n = 31; break;
-	case L'W': case L'w': n = 32; break;
-	case L'X': case L'x': n = 33; break;
-	case L'Y': case L'y': n = 34; break;
-	case L'Z': case L'z': n = 35; break;
-	default: n = -1; break; /* error */
-	}
-
-	return n;
-}
diff --git a/tests/stdio_test.cpp b/tests/stdio_test.cpp
index 5e4e068..1acf989 100644
--- a/tests/stdio_test.cpp
+++ b/tests/stdio_test.cpp
@@ -3035,3 +3035,139 @@
   EXPECT_EQ(std::wstring(L"<0>"), buf);
 #pragma clang diagnostic pop
 }
+
+TEST(STDIO_TEST, scanf_i_decimal) {
+  int i;
+  EXPECT_EQ(1, sscanf("<123789>", "<%i>", &i));
+  EXPECT_EQ(123789, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, sscanf("1234567890abcdefg", "%lli%c", &lli, &ch));
+  EXPECT_EQ(1234567890, lli);
+  EXPECT_EQ('a', ch);
+}
+
+TEST(STDIO_TEST, scanf_i_hex) {
+  int i;
+  EXPECT_EQ(1, sscanf("<0x123abf>", "<%i>", &i));
+  EXPECT_EQ(0x123abf, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, sscanf("0x1234567890abcdefg", "%lli%c", &lli, &ch));
+  EXPECT_EQ(0x1234567890abcdefLL, lli);
+  EXPECT_EQ('g', ch);
+}
+
+TEST(STDIO_TEST, scanf_i_octal) {
+  int i;
+  EXPECT_EQ(1, sscanf("<01234567>", "<%i>", &i));
+  EXPECT_EQ(01234567, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, sscanf("010234567890abcdefg", "%lli%c", &lli, &ch));
+  EXPECT_EQ(010234567, lli);
+  EXPECT_EQ('8', ch);
+}
+
+TEST(STDIO_TEST, scanf_i_binary) {
+  int i;
+  EXPECT_EQ(1, sscanf("<0b101>", "<%i>", &i));
+  EXPECT_EQ(0b101, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, sscanf("0b10234567890abcdefg", "%lli%c", &lli, &ch));
+  EXPECT_EQ(0b10, lli);
+  EXPECT_EQ('2', ch);
+}
+
+TEST(STDIO_TEST, wscanf_i_decimal) {
+  int i;
+  EXPECT_EQ(1, swscanf(L"<123789>", L"<%i>", &i));
+  EXPECT_EQ(123789, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, swscanf(L"1234567890abcdefg", L"%lli%c", &lli, &ch));
+  EXPECT_EQ(1234567890, lli);
+  EXPECT_EQ('a', ch);
+}
+
+TEST(STDIO_TEST, wscanf_i_hex) {
+  int i;
+  EXPECT_EQ(1, swscanf(L"<0x123abf>", L"<%i>", &i));
+  EXPECT_EQ(0x123abf, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, swscanf(L"0x1234567890abcdefg", L"%lli%c", &lli, &ch));
+  EXPECT_EQ(0x1234567890abcdefLL, lli);
+  EXPECT_EQ('g', ch);
+}
+
+TEST(STDIO_TEST, wscanf_i_octal) {
+  int i;
+  EXPECT_EQ(1, swscanf(L"<01234567>", L"<%i>", &i));
+  EXPECT_EQ(01234567, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, swscanf(L"010234567890abcdefg", L"%lli%c", &lli, &ch));
+  EXPECT_EQ(010234567, lli);
+  EXPECT_EQ('8', ch);
+}
+
+TEST(STDIO_TEST, wscanf_i_binary) {
+  int i;
+  EXPECT_EQ(1, swscanf(L"<0b101>", L"<%i>", &i));
+  EXPECT_EQ(0b101, i);
+
+  long long int lli;
+  char ch;
+  EXPECT_EQ(2, swscanf(L"0b10234567890abcdefg", L"%lli%c", &lli, &ch));
+  EXPECT_EQ(0b10, lli);
+  EXPECT_EQ('2', ch);
+}
+
+TEST(STDIO_TEST, scanf_b) {
+  // Our clang doesn't know about %b yet.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wformat"
+#pragma clang diagnostic ignored "-Wformat-invalid-specifier"
+  int i;
+  char ch;
+  EXPECT_EQ(2, sscanf("<1012>", "<%b%c>", &i, &ch));
+  EXPECT_EQ(0b101, i);
+  EXPECT_EQ('2', ch);
+  EXPECT_EQ(1, sscanf("<00000101>", "<%08b>", &i));
+  EXPECT_EQ(0b00000101, i);
+  EXPECT_EQ(1, sscanf("<0b1010>", "<%b>", &i));
+  EXPECT_EQ(0b1010, i);
+  EXPECT_EQ(2, sscanf("-0b", "%i%c", &i, &ch));
+  EXPECT_EQ(0, i);
+  EXPECT_EQ('b', ch);
+#pragma clang diagnostic pop
+}
+
+TEST(STDIO_TEST, swscanf_b) {
+  // Our clang doesn't know about %b yet.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wformat"
+#pragma clang diagnostic ignored "-Wformat-invalid-specifier"
+  int i;
+  char ch;
+  EXPECT_EQ(2, swscanf(L"<1012>", L"<%b%c>", &i, &ch));
+  EXPECT_EQ(0b101, i);
+  EXPECT_EQ('2', ch);
+  EXPECT_EQ(1, swscanf(L"<00000101>", L"<%08b>", &i));
+  EXPECT_EQ(0b00000101, i);
+  EXPECT_EQ(1, swscanf(L"<0b1010>", L"<%b>", &i));
+  EXPECT_EQ(0b1010, i);
+  EXPECT_EQ(2, swscanf(L"-0b", L"%i%c", &i, &ch));
+  EXPECT_EQ(0, i);
+  EXPECT_EQ('b', ch);
+#pragma clang diagnostic pop
+}
diff --git a/tests/stdlib_test.cpp b/tests/stdlib_test.cpp
index 465e61a..f507e08 100644
--- a/tests/stdlib_test.cpp
+++ b/tests/stdlib_test.cpp
@@ -843,11 +843,19 @@
   ASSERT_EQ(T(-123), fn("-123", &end_p, 10));
   ASSERT_EQ(T(123), fn("+123", &end_p, 10));
 
+  // If we see "0b" *not* followed by a binary digit, we shouldn't swallow the 'b'.
+  ASSERT_EQ(T(0), fn("0b", &end_p, 2));
+  ASSERT_EQ('b', *end_p);
+
+  // Binary (the "0b" prefix) is case-insensitive.
+  ASSERT_EQ(T(0b101), fn("0b101", &end_p, 0));
+  ASSERT_EQ(T(0b101), fn("0B101", &end_p, 0));
+
   // If we see "0x" *not* followed by a hex digit, we shouldn't swallow the 'x'.
   ASSERT_EQ(T(0), fn("0xy", &end_p, 16));
   ASSERT_EQ('x', *end_p);
 
-  // Hexadecimal (both the 0x and the digits) is case-insensitive.
+  // Hexadecimal (both the "0x" prefix and the digits) is case-insensitive.
   ASSERT_EQ(T(0xab), fn("0xab", &end_p, 0));
   ASSERT_EQ(T(0xab), fn("0Xab", &end_p, 0));
   ASSERT_EQ(T(0xab), fn("0xAB", &end_p, 0));
diff --git a/tests/wchar_test.cpp b/tests/wchar_test.cpp
index 85a75ec..16d4348 100644
--- a/tests/wchar_test.cpp
+++ b/tests/wchar_test.cpp
@@ -460,6 +460,7 @@
   TestSingleWcsToInt(fn, L"   123 45", 0, static_cast<T>(123), 6);
   TestSingleWcsToInt(fn, L"  -123", 0, static_cast<T>(-123), 6);
   TestSingleWcsToInt(fn, L"0x10000", 0, static_cast<T>(65536), 7);
+  TestSingleWcsToInt(fn, L"0b1011", 0, static_cast<T>(0b1011), 6);
 }
 
 template <typename T>