diff --git a/libc/docs/configure.rst b/libc/docs/configure.rst
index 8d53390ae19bf..109412225634f 100644
--- a/libc/docs/configure.rst
+++ b/libc/docs/configure.rst
@@ -29,7 +29,7 @@ to learn about the defaults for your platform and target.
     - ``LIBC_CONF_ENABLE_STRONG_STACK_PROTECTOR``: Enable -fstack-protector-strong to defend against stack smashing attack.
     - ``LIBC_CONF_KEEP_FRAME_POINTER``: Keep frame pointer in functions for better debugging experience.
 * **"errno" options**
-    - ``LIBC_CONF_ERRNO_MODE``: The implementation used for errno, acceptable values are LIBC_ERRNO_MODE_DEFAULT, LIBC_ERRNO_MODE_UNDEFINED, LIBC_ERRNO_MODE_THREAD_LOCAL, LIBC_ERRNO_MODE_SHARED, LIBC_ERRNO_MODE_EXTERNAL, and LIBC_ERRNO_MODE_SYSTEM.
+    - ``LIBC_CONF_ERRNO_MODE``: The implementation used for errno, acceptable values are LIBC_ERRNO_MODE_DEFAULT, LIBC_ERRNO_MODE_UNDEFINED, LIBC_ERRNO_MODE_THREAD_LOCAL, LIBC_ERRNO_MODE_SHARED, LIBC_ERRNO_MODE_EXTERNAL, LIBC_ERRNO_MODE_SYSTEM, and LIBC_ERRNO_MODE_SYSTEM_INLINE.
 * **"general" options**
     - ``LIBC_ADD_NULL_CHECKS``: Add nullptr checks in the library's implementations to some functions for which passing nullptr is undefined behavior.
 * **"math" options**
diff --git a/libc/test/src/stdio/fgetc_test.cpp b/libc/test/src/stdio/fgetc_test.cpp
index 7c652f666a8f3..1faa49112fb63 100644
--- a/libc/test/src/stdio/fgetc_test.cpp
+++ b/libc/test/src/stdio/fgetc_test.cpp
@@ -33,6 +33,7 @@ class LlvmLibcGetcTest : public LIBC_NAMESPACE::testing::ErrnoCheckingTest {
     // This is an error and not a real EOF.
     ASSERT_EQ(LIBC_NAMESPACE::feof(file), 0);
     ASSERT_NE(LIBC_NAMESPACE::ferror(file), 0);
+    ASSERT_ERRNO_FAILURE();
 
     ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
 
diff --git a/libc/test/src/stdio/fgetc_unlocked_test.cpp b/libc/test/src/stdio/fgetc_unlocked_test.cpp
index f4471dd82df15..7b2efe642fb5e 100644
--- a/libc/test/src/stdio/fgetc_unlocked_test.cpp
+++ b/libc/test/src/stdio/fgetc_unlocked_test.cpp
@@ -36,6 +36,7 @@ class LlvmLibcGetcTest : public LIBC_NAMESPACE::testing::ErrnoCheckingTest {
     // This is an error and not a real EOF.
     ASSERT_EQ(LIBC_NAMESPACE::feof(file), 0);
     ASSERT_NE(LIBC_NAMESPACE::ferror(file), 0);
+    ASSERT_ERRNO_FAILURE();
 
     ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
 
diff --git a/libc/test/src/stdio/fgets_test.cpp b/libc/test/src/stdio/fgets_test.cpp
index c00a9256af52d..2d7c68d490811 100644
--- a/libc/test/src/stdio/fgets_test.cpp
+++ b/libc/test/src/stdio/fgets_test.cpp
@@ -36,6 +36,7 @@ TEST_F(LlvmLibcFgetsTest, WriteAndReadCharacters) {
   // This is an error and not a real EOF.
   ASSERT_EQ(LIBC_NAMESPACE::feof(file), 0);
   ASSERT_NE(LIBC_NAMESPACE::ferror(file), 0);
+  ASSERT_ERRNO_FAILURE();
 
   ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
 
diff --git a/libc/test/src/stdio/setvbuf_test.cpp b/libc/test/src/stdio/setvbuf_test.cpp
index 4144bc1bef447..a0936ba79ef73 100644
--- a/libc/test/src/stdio/setvbuf_test.cpp
+++ b/libc/test/src/stdio/setvbuf_test.cpp
@@ -11,6 +11,7 @@
 #include "src/stdio/fread.h"
 #include "src/stdio/fwrite.h"
 #include "src/stdio/setvbuf.h"
+#include "test/UnitTest/ErrnoCheckingTest.h"
 #include "test/UnitTest/Test.h"
 
 #include "hdr/stdio_macros.h"