diff --git a/common.h b/common.h
index 4228e71..33c5ba0 100644
--- a/common.h
+++ b/common.h
@@ -37,9 +37,13 @@
 // The reason argument provided in "--reason=".
 extern const char* reason;
 
-// fopen a file, mounting volumes and making parent dirs as necessary.
+// fopen(3)'s the given file, by mounting volumes and making parent dirs as necessary. Returns the
+// file pointer, or nullptr on error.
 FILE* fopen_path(const std::string& path, const char* mode);
 
+// In turn fflush(3)'s, fsync(3)'s and fclose(3)'s the given stream.
+void check_and_fclose(FILE* fp, const std::string& name);
+
 void ui_print(const char* format, ...) __printflike(1, 2);
 
 bool is_ro_debuggable();