diff --git a/modules/src/print/doprnt.c b/modules/src/print/doprnt.c
index a77b7d2c1..1d888e570 100644
--- a/modules/src/print/doprnt.c
+++ b/modules/src/print/doprnt.c
@@ -16,7 +16,7 @@
 	%d = int
 $ */
 void
-doprnt(File *fp, char *fmt, va_list argp)
+doprnt(File *fp, const char *fmt, va_list argp)
 {
 	char buf[SSIZE];
 
diff --git a/modules/src/print/format.c b/modules/src/print/format.c
index 2ad920bc8..e03717918 100644
--- a/modules/src/print/format.c
+++ b/modules/src/print/format.c
@@ -35,7 +35,7 @@ integral(int c)
 	%d = int
 $ */
 int
-_format(char *buf, char *fmt, va_list argp)
+_format(char *buf, const char *fmt, va_list argp)
 {
 	register char *pf = fmt;
 	register char *pb = buf;
diff --git a/modules/src/print/fprint.c b/modules/src/print/fprint.c
index c401858a9..6b5b8a389 100644
--- a/modules/src/print/fprint.c
+++ b/modules/src/print/fprint.c
@@ -17,7 +17,7 @@
 $ */
 /*VARARGS*/
 void
-fprint(File *fp, char *fmt, ...)
+fprint(File *fp, const char *fmt, ...)
 {
 	va_list args;
 	char buf[SSIZE];
diff --git a/modules/src/print/print.c b/modules/src/print/print.c
index cd9346e98..2e1256a54 100644
--- a/modules/src/print/print.c
+++ b/modules/src/print/print.c
@@ -17,7 +17,7 @@
 $ */
 /*VARARGS*/
 void
-print(char *fmt, ...)
+print(const char *fmt, ...)
 {
 	va_list args;
 	char buf[SSIZE];
diff --git a/modules/src/print/print.h b/modules/src/print/print.h
index 56372376a..974e4bf1b 100644
--- a/modules/src/print/print.h
+++ b/modules/src/print/print.h
@@ -9,10 +9,10 @@
 
 #include <stdarg.h>
 
-void print(char *fmt, ...);
-void fprint(File *f, char *fmt, ...);
-void doprnt(File *f, char *fmt, va_list ap);
-int _format(char *buf, char *fmt, va_list ap);
-char *sprint(char *buf, char *fmt, ...);
+void print(const char *fmt, ...);
+void fprint(File *f, const char *fmt, ...);
+void doprnt(File *f, const char *fmt, va_list ap);
+int _format(char *buf, const char *fmt, va_list ap);
+char *sprint(char *buf, const char *fmt, ...);
 
 #endif /* __PRINT_INCLUDED__ */
diff --git a/modules/src/print/sprint.c b/modules/src/print/sprint.c
index d88b47e69..7c9dbf9b0 100644
--- a/modules/src/print/sprint.c
+++ b/modules/src/print/sprint.c
@@ -17,7 +17,7 @@
 $ */
 /*VARARGS*/
 char *
-sprint(char *buf, char *fmt, ...)
+sprint(char *buf, const char *fmt, ...)
 {
 	va_list args;
 
diff --git a/util/misc/convert.c b/util/misc/convert.c
index ec38761fa..9bdc12011 100644
--- a/util/misc/convert.c
+++ b/util/misc/convert.c
@@ -16,8 +16,10 @@ static char rcsid[] = "$Id$";
 	linked.
 */
 
+#include <stdarg.h>
 #include <stdlib.h>
 #include "system.h"
+#include "print.h"
 #include "em_pseu.h"
 #include "em_mnem.h"
 #include "em_spec.h"
@@ -30,8 +32,11 @@ char *filename;			/* Name of input file */
 int errors;			/* Number of errors */
 extern char *C_error;
 
-main(argc,argv)
-	char **argv;
+void error(const char *, ...);
+void fatal(const char *, ...);
+
+int
+main(int argc, char **argv)
 {
 	struct e_instr buf;
 	register struct e_instr *p = &buf;
@@ -66,27 +71,32 @@ main(argc,argv)
 	}
 	C_close();
 	EM_close();
-	exit(errors);
+	exit(errors ? 1 : 0);
 }
 
 /* VARARGS */
-error(s,a1,a2,a3,a4)
-	char *s;
+void
+error(const char *s, ...)
 {
+	va_list ap;
+	va_start(ap, s);
 	fprint(STDERR,
 		"%s, line %d: ",
 		filename ? filename : "standard input",
 		EM_lineno);
-	fprint(STDERR,s,a1,a2,a3,a4);
+	doprnt(STDERR, s, ap);
 	fprint(STDERR, "\n");
 	errors++;
+	va_end(ap);
 }
 
 /* VARARGS */
-fatal(s,a1,a2,a3,a4)
-	char *s;
+void
+fatal(const char *s, ...)
 {
+	va_list ap;
+	va_start(ap, s);
 	if (C_busy()) C_close();
-	error(s,a1,a2,a3,a4);
+	error(s, ap);
 	exit(1);
 }