diff --git a/mainwindow.h b/mainwindow.h
index 2680262db..913d80ded 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -358,8 +358,8 @@ extern int ptt(int nport, int ntx, int* iptt, int* nopen);
 
 extern "C" {
 //----------------------------------------------------- C and Fortran routines
-void symspec_(int* k, int* ntrperiod, int* nsps, int* ingain, int* nb,
-              int* m_NBslider, float* px, float s[], float red[],
+void symspec_(int* k, int* ntrperiod, int* nsps, int* ingain,
+              float* px, float s[], float red[],
               float* df3, int* nhsym, int* npts8);
 
 void genjt9_(char* msg, int* ichk, char* msgsent, int itone[],