diff --git a/libc/include/bits/sysconf.h b/libc/include/bits/sysconf.h
index 2cbbb11..8607adf 100644
--- a/libc/include/bits/sysconf.h
+++ b/libc/include/bits/sysconf.h
@@ -73,6 +73,7 @@
 #define _SC_XOPEN_LEGACY        0x0024
 #define _SC_ATEXIT_MAX          0x0025
 #define _SC_IOV_MAX             0x0026
+#define _SC_UIO_MAXIOV _SC_IOV_MAX
 #define _SC_PAGESIZE            0x0027
 #define _SC_PAGE_SIZE           0x0028
 #define _SC_XOPEN_UNIX          0x0029
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 1f7f555..da083de 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -886,6 +886,8 @@
   VerifySysconf(_SC_XOPEN_VERSION, "_SC_XOPEN_VERSION", [](long v){return v == _XOPEN_VERSION && errno == 0;});
   VERIFY_SYSCONF_POSITIVE(_SC_ATEXIT_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_IOV_MAX);
+  VERIFY_SYSCONF_POSITIVE(_SC_UIO_MAXIOV);
+  EXPECT_EQ(sysconf(_SC_IOV_MAX), sysconf(_SC_UIO_MAXIOV));
   VERIFY_SYSCONF_POSITIVE(_SC_PAGESIZE);
   VERIFY_SYSCONF_POSITIVE(_SC_PAGE_SIZE);
   VerifySysconf(_SC_PAGE_SIZE, "_SC_PAGE_SIZE",