diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index d8b00e3a..6abed458 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -208,6 +208,9 @@ extern "C"
     /* Pipe a stream to or from a process. */
     FILE* popen(const char* command, const char* type);
 
+    /* Close a pipe stream. */
+    int pclose(FILE* stream);
+
     /* Return the path of the process's controlling terminal (always /dev/tty on Luna). */
     char* ctermid(char* s);