diff --git a/libc/Android.bp b/libc/Android.bp
index f326db3..f0930fe 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1262,6 +1262,7 @@
         "bionic/ifaddrs.cpp",
         "bionic/inotify_init.cpp",
         "bionic/ioctl.cpp",
+        "bionic/langinfo.cpp",
         "bionic/lchown.cpp",
         "bionic/lfs64_support.cpp",
         "bionic/__libc_current_sigrtmax.cpp",
diff --git a/libc/bionic/langinfo.cpp b/libc/bionic/langinfo.cpp
new file mode 100644
index 0000000..6f5057c
--- /dev/null
+++ b/libc/bionic/langinfo.cpp
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2016 The Android Open Source 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:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+
+#include <langinfo.h>
+
+#include <stdlib.h>
+
+char* nl_langinfo(nl_item item) {
+  const char* result = "";
+  switch (item) {
+    case CODESET: result = (MB_CUR_MAX == 1) ? "ASCII" : "UTF-8"; break;
+
+    case D_T_FMT: result = "%F %T %z"; break;
+    case D_FMT: result = "%F"; break;
+    case T_FMT: result = "%T"; break;
+    case T_FMT_AMPM: result = "%I:%M:%S %p"; break;
+    case AM_STR: result = "AM"; break;
+    case PM_STR: result = "PM"; break;
+    case DAY_1: result = "Sunday"; break;
+    case DAY_2: result = "Monday"; break;
+    case DAY_3: result = "Tuesday"; break;
+    case DAY_4: result = "Wednesday"; break;
+    case DAY_5: result = "Thursday"; break;
+    case DAY_6: result = "Friday"; break;
+    case DAY_7: result = "Saturday"; break;
+    case ABDAY_1: result = "Sun"; break;
+    case ABDAY_2: result = "Mon"; break;
+    case ABDAY_3: result = "Tue"; break;
+    case ABDAY_4: result = "Wed"; break;
+    case ABDAY_5: result = "Thu"; break;
+    case ABDAY_6: result = "Fri"; break;
+    case ABDAY_7: result = "Sat"; break;
+    case MON_1: result = "January"; break;
+    case MON_2: result = "February"; break;
+    case MON_3: result = "March"; break;
+    case MON_4: result = "April"; break;
+    case MON_5: result = "May"; break;
+    case MON_6: result = "June"; break;
+    case MON_7: result = "July"; break;
+    case MON_8: result = "August"; break;
+    case MON_9: result = "September"; break;
+    case MON_10: result = "October"; break;
+    case MON_11: result = "November"; break;
+    case MON_12: result = "December"; break;
+    case ABMON_1: result = "Jan"; break;
+    case ABMON_2: result = "Feb"; break;
+    case ABMON_3: result = "Mar"; break;
+    case ABMON_4: result = "Apr"; break;
+    case ABMON_5: result = "May"; break;
+    case ABMON_6: result = "Jun"; break;
+    case ABMON_7: result = "Jul"; break;
+    case ABMON_8: result = "Aug"; break;
+    case ABMON_9: result = "Sep"; break;
+    case ABMON_10: result = "Oct"; break;
+    case ABMON_11: result = "Nov"; break;
+    case ABMON_12: result = "Dec"; break;
+    case ERA: result = ""; break;
+    case ERA_D_FMT: result = ""; break;
+    case ERA_D_T_FMT: result = ""; break;
+    case ERA_T_FMT: result = ""; break;
+    case ALT_DIGITS: result = ""; break;
+
+    case RADIXCHAR: result = "."; break;
+    case THOUSEP: result = ""; break;
+
+    case YESEXPR: result = "^[yY]"; break;
+    case NOEXPR: result = "^[nN]"; break;
+
+    case CRNCYSTR: result = ""; break;
+
+    default: break;
+  }
+  return const_cast<char*>(result);
+}
+
+char* nl_langinfo_l(nl_item item, locale_t) {
+  return nl_langinfo(item);
+}
diff --git a/libc/include/langinfo.h b/libc/include/langinfo.h
new file mode 100644
index 0000000..5c884ac
--- /dev/null
+++ b/libc/include/langinfo.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2016 The Android Open Source 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:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+
+#ifndef _LANGINFO_H_
+#define _LANGINFO_H_
+
+#include <sys/cdefs.h>
+
+#include <nl_types.h>
+#include <xlocale.h>
+
+__BEGIN_DECLS
+
+#define CODESET 1
+#define D_T_FMT 2
+#define D_FMT 3
+#define T_FMT 4
+#define T_FMT_AMPM 5
+#define AM_STR 6
+#define PM_STR 7
+#define DAY_1 8
+#define DAY_2 9
+#define DAY_3 10
+#define DAY_4 11
+#define DAY_5 12
+#define DAY_6 13
+#define DAY_7 14
+#define ABDAY_1 15
+#define ABDAY_2 16
+#define ABDAY_3 17
+#define ABDAY_4 18
+#define ABDAY_5 19
+#define ABDAY_6 20
+#define ABDAY_7 21
+#define MON_1 22
+#define MON_2 23
+#define MON_3 24
+#define MON_4 25
+#define MON_5 26
+#define MON_6 27
+#define MON_7 28
+#define MON_8 29
+#define MON_9 30
+#define MON_10 31
+#define MON_11 32
+#define MON_12 33
+#define ABMON_1 34
+#define ABMON_2 35
+#define ABMON_3 36
+#define ABMON_4 37
+#define ABMON_5 38
+#define ABMON_6 39
+#define ABMON_7 40
+#define ABMON_8 41
+#define ABMON_9 42
+#define ABMON_10 43
+#define ABMON_11 44
+#define ABMON_12 45
+#define ERA 46
+#define ERA_D_FMT 47
+#define ERA_D_T_FMT 48
+#define ERA_T_FMT 49
+#define ALT_DIGITS 50
+#define RADIXCHAR 51
+#define THOUSEP 52
+#define YESEXPR 53
+#define NOEXPR 54
+#define CRNCYSTR 55
+
+char* nl_langinfo(nl_item) __INTRODUCED_IN_FUTURE;
+char* nl_langinfo_l(nl_item, locale_t) __INTRODUCED_IN_FUTURE;
+
+__END_DECLS
+
+#endif
diff --git a/libc/libc.arm.map b/libc/libc.arm.map
index eb75e8f..f9c5ede 100644
--- a/libc/libc.arm.map
+++ b/libc/libc.arm.map
@@ -1288,6 +1288,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/libc.arm64.map b/libc/libc.arm64.map
index 28755d4..179d8bf 100644
--- a/libc/libc.arm64.map
+++ b/libc/libc.arm64.map
@@ -1210,6 +1210,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index 1fba8ee..f122937 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1313,6 +1313,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/libc.mips.map b/libc/libc.mips.map
index f61f615..a969703 100644
--- a/libc/libc.mips.map
+++ b/libc/libc.mips.map
@@ -1272,6 +1272,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/libc.mips64.map b/libc/libc.mips64.map
index 28755d4..179d8bf 100644
--- a/libc/libc.mips64.map
+++ b/libc/libc.mips64.map
@@ -1210,6 +1210,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/libc.x86.map b/libc/libc.x86.map
index a166361..dfa839e 100644
--- a/libc/libc.x86.map
+++ b/libc/libc.x86.map
@@ -1270,6 +1270,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/libc.x86_64.map b/libc/libc.x86_64.map
index 28755d4..179d8bf 100644
--- a/libc/libc.x86_64.map
+++ b/libc/libc.x86_64.map
@@ -1210,6 +1210,8 @@
     msgget; # future
     msgrcv; # future
     msgsnd; # future
+    nl_langinfo; # future
+    nl_langinfo_l; # future
     pthread_getname_np; # future
     quotactl; # future
     semctl; # future
diff --git a/libc/upstream-openbsd/lib/libc/include/langinfo.h b/libc/upstream-openbsd/lib/libc/include/langinfo.h
deleted file mode 100644
index a871ab8..0000000
--- a/libc/upstream-openbsd/lib/libc/include/langinfo.h
+++ /dev/null
@@ -1,3 +0,0 @@
-/* Hack to build "vfprintf.c". */
-#define RADIXCHAR 1
-#define nl_langinfo(i) ((i == RADIXCHAR) ? (char*) "." : NULL)
diff --git a/tests/Android.bp b/tests/Android.bp
index 3e1e13b..362fe39 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -68,6 +68,7 @@
         "grp_pwd_test.cpp",
         "ifaddrs_test.cpp",
         "inttypes_test.cpp",
+        "langinfo_test.cpp",
         "libc_logging_test.cpp",
         "libgen_basename_test.cpp",
         "libgen_test.cpp",
diff --git a/tests/langinfo_test.cpp b/tests/langinfo_test.cpp
new file mode 100644
index 0000000..6eae8bc
--- /dev/null
+++ b/tests/langinfo_test.cpp
@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2016 The Android Open Source 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:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+
+#include <gtest/gtest.h>
+
+#include <langinfo.h>
+
+TEST(langinfo, category_CTYPE) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+  EXPECT_STREQ("UTF-8", nl_langinfo(CODESET));
+}
+
+TEST(langinfo, category_TIME) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+#if defined(__BIONIC__)
+  // bionic's C locale is ISO rather than en_US.
+  EXPECT_STREQ("%F %T %z", nl_langinfo(D_T_FMT));
+  EXPECT_STREQ("%F", nl_langinfo(D_FMT));
+#else
+  EXPECT_STREQ("%a %d %b %Y %r %Z", nl_langinfo(D_T_FMT));
+  EXPECT_STREQ("%m/%d/%Y", nl_langinfo(D_FMT));
+#endif
+  EXPECT_STREQ("%T", nl_langinfo(T_FMT));
+  EXPECT_STREQ("%I:%M:%S %p", nl_langinfo(T_FMT_AMPM));
+  EXPECT_STREQ("AM", nl_langinfo(AM_STR));
+  EXPECT_STREQ("PM", nl_langinfo(PM_STR));
+  EXPECT_STREQ("Sunday", nl_langinfo(DAY_1));
+  EXPECT_STREQ("Monday", nl_langinfo(DAY_2));
+  EXPECT_STREQ("Tuesday", nl_langinfo(DAY_3));
+  EXPECT_STREQ("Wednesday", nl_langinfo(DAY_4));
+  EXPECT_STREQ("Thursday", nl_langinfo(DAY_5));
+  EXPECT_STREQ("Friday", nl_langinfo(DAY_6));
+  EXPECT_STREQ("Saturday", nl_langinfo(DAY_7));
+  EXPECT_STREQ("Sun", nl_langinfo(ABDAY_1));
+  EXPECT_STREQ("Mon", nl_langinfo(ABDAY_2));
+  EXPECT_STREQ("Tue", nl_langinfo(ABDAY_3));
+  EXPECT_STREQ("Wed", nl_langinfo(ABDAY_4));
+  EXPECT_STREQ("Thu", nl_langinfo(ABDAY_5));
+  EXPECT_STREQ("Fri", nl_langinfo(ABDAY_6));
+  EXPECT_STREQ("Sat", nl_langinfo(ABDAY_7));
+  EXPECT_STREQ("January", nl_langinfo(MON_1));
+  EXPECT_STREQ("February", nl_langinfo(MON_2));
+  EXPECT_STREQ("March", nl_langinfo(MON_3));
+  EXPECT_STREQ("April", nl_langinfo(MON_4));
+  EXPECT_STREQ("May", nl_langinfo(MON_5));
+  EXPECT_STREQ("June", nl_langinfo(MON_6));
+  EXPECT_STREQ("July", nl_langinfo(MON_7));
+  EXPECT_STREQ("August", nl_langinfo(MON_8));
+  EXPECT_STREQ("September", nl_langinfo(MON_9));
+  EXPECT_STREQ("October", nl_langinfo(MON_10));
+  EXPECT_STREQ("November", nl_langinfo(MON_11));
+  EXPECT_STREQ("December", nl_langinfo(MON_12));
+  EXPECT_STREQ("Jan", nl_langinfo(ABMON_1));
+  EXPECT_STREQ("Feb", nl_langinfo(ABMON_2));
+  EXPECT_STREQ("Mar", nl_langinfo(ABMON_3));
+  EXPECT_STREQ("Apr", nl_langinfo(ABMON_4));
+  EXPECT_STREQ("May", nl_langinfo(ABMON_5));
+  EXPECT_STREQ("Jun", nl_langinfo(ABMON_6));
+  EXPECT_STREQ("Jul", nl_langinfo(ABMON_7));
+  EXPECT_STREQ("Aug", nl_langinfo(ABMON_8));
+  EXPECT_STREQ("Sep", nl_langinfo(ABMON_9));
+  EXPECT_STREQ("Oct", nl_langinfo(ABMON_10));
+  EXPECT_STREQ("Nov", nl_langinfo(ABMON_11));
+  EXPECT_STREQ("Dec", nl_langinfo(ABMON_12));
+  EXPECT_STREQ("", nl_langinfo(ERA));
+  EXPECT_STREQ("", nl_langinfo(ERA_D_FMT));
+  EXPECT_STREQ("", nl_langinfo(ERA_D_T_FMT));
+  EXPECT_STREQ("", nl_langinfo(ERA_T_FMT));
+  EXPECT_STREQ("", nl_langinfo(ALT_DIGITS));
+}
+
+TEST(langinfo, category_NUMERIC) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+  EXPECT_STREQ(".", nl_langinfo(RADIXCHAR));
+  EXPECT_STREQ("", nl_langinfo(THOUSEP));
+}
+
+TEST(langinfo, category_MESSAGES) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+  EXPECT_STREQ("^[yY]", nl_langinfo(YESEXPR));
+  EXPECT_STREQ("^[nN]", nl_langinfo(NOEXPR));
+}
+
+TEST(langinfo, category_MONETARY) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+  // POSIX says that if the currency symbol is the empty string (as it is for
+  // the C locale), an implementation can return the empty string and not
+  // include the leading [+-.] that signifies where the currency symbol should
+  // appear. For consistency with localeconv (which POSIX says to prefer for
+  // RADIXCHAR, THOUSEP, and CRNCYSTR) we return the empty string. glibc
+  // disagrees.
+#if defined(__BIONIC__)
+  EXPECT_STREQ("", nl_langinfo(CRNCYSTR));
+#else
+  EXPECT_STREQ("-", nl_langinfo(CRNCYSTR));
+#endif
+}
+
+TEST(langinfo, invalid) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+  EXPECT_STREQ("", nl_langinfo(-1));
+  EXPECT_STREQ("", nl_langinfo(0));
+  EXPECT_STREQ("", nl_langinfo(666));
+}
+
+TEST(langinfo, matches_localeconv) {
+  ASSERT_STREQ("C.UTF-8", setlocale(LC_ALL, "C.UTF-8"));
+
+  EXPECT_STREQ(localeconv()->decimal_point, nl_langinfo(RADIXCHAR));
+  EXPECT_STREQ(localeconv()->thousands_sep, nl_langinfo(THOUSEP));
+#if defined(__BIONIC__)
+  // (See comment in category_MONETARY test.)
+  EXPECT_STREQ(localeconv()->currency_symbol, nl_langinfo(CRNCYSTR));
+#endif
+}