diff --git a/libc/stdio/stdio_ext.cpp b/libc/stdio/stdio_ext.cpp
index 8cf4f4b..e17b62a 100644
--- a/libc/stdio/stdio_ext.cpp
+++ b/libc/stdio/stdio_ext.cpp
@@ -72,6 +72,10 @@
   fflush(NULL);
 }
 
+void __fseterr(FILE* fp) {
+  fp->_flags |= __SERR;
+}
+
 int __fsetlocking(FILE* fp, int type) {
   int old_state = _EXT(fp)->_caller_handles_locking ? FSETLOCKING_BYCALLER : FSETLOCKING_INTERNAL;
   if (type == FSETLOCKING_QUERY) {