diff --git a/libc/include/stdio_ext.h b/libc/include/stdio_ext.h
index 2f0f438..b8aa68d 100644
--- a/libc/include/stdio_ext.h
+++ b/libc/include/stdio_ext.h
@@ -45,6 +45,8 @@
 size_t __fpending(FILE* __fp) __INTRODUCED_IN(23);
 void _flushlbf(void) __INTRODUCED_IN(23);
 
+void __fseterr(FILE* __fp) __INTRODUCED_IN(28);
+
 #define FSETLOCKING_QUERY 0
 #define FSETLOCKING_INTERNAL 1
 #define FSETLOCKING_BYCALLER 2