1 files changed, 5 insertions, 1 deletions
diff --git a/nasm.h b/nasm.h
index 98823be8..0e6482ba 100644
--- a/nasm.h
+++ b/nasm.h
@@ -182,6 +182,11 @@ typedef struct {
      * Reverse the effects of uplevel.
      */
     void (*downlevel) (int);
+
+    /*
+     * Called on a warning or error, with the error message.
+     */
+    void (*error)(int severity, const char *pfx, const char *msg);
 } ListGen;
 
 /*
@@ -941,7 +946,6 @@ struct ofmt {
  */
 
 struct dfmt {
-
     /*
      * This is a short (one-liner) description of the type of
      * output generated by the driver.