diff --git a/src/shputils.c b/src/shputils.c
index 924bc9e..98eb961 100644
--- a/src/shputils.c
+++ b/src/shputils.c
@@ -185,7 +185,7 @@ void error(void);
 /*                             openfiles()                              */
 /************************************************************************/
 
-void openfiles() {
+void openfiles(void) {
 /* -------------------------------------------------------------------- */
 /*      Open the DBF file.                                              */
 /* -------------------------------------------------------------------- */
@@ -290,7 +290,7 @@ int i;
 /*	Find matching fields in the append file.                        */
 /*      Output file must have zero records to add any new fields.       */
 /* -------------------------------------------------------------------- */
-void mergefields()
+void mergefields(void)
 {
     int i,j;
     ti = DBFGetFieldCount( hDBF );
@@ -353,7 +353,7 @@ void mergefields()
 }
 
 
-void findselect()
+void findselect(void)
 {
     /* Find the select field name */
     iselectitem = -1;
@@ -374,7 +374,7 @@ void findselect()
 
 }
 
-void showitems()
+void showitems(void)
 {
     char      stmp[40],slow[40],shigh[40];
     double    dtmp,dlow,dhigh,dsum,mean;
@@ -459,7 +459,7 @@ void showitems()
     dgprintf("\n");
 }
 
-int selectrec()
+int selectrec(void)
 {
     long int value, ty;
 
@@ -491,7 +491,7 @@ int selectrec()
 }
 
 
-void check_theme_bnd()
+void check_theme_bnd(void)
 {
     if ( (adfBoundsMin[0] >= cxmin) && (adfBoundsMax[0] <= cxmax) &&
          (adfBoundsMin[1] >= cymin) && (adfBoundsMax[1] <= cymax) )
@@ -513,7 +513,7 @@ void check_theme_bnd()
         dgprintf("WARNING: Theme is outside the clip area."); /** SKIP THEME  **/
 }
 
-int clip_boundary()
+int clip_boundary(void)
 {
     int  inside;
     int  prev_outside;
@@ -692,7 +692,7 @@ double findunit(char *unit)
 /* -------------------------------------------------------------------- */
 /*      Display a usage message.                                        */
 /* -------------------------------------------------------------------- */
-void error()
+void error(void)
 {
     dgprintf( "The program will append to an existing shape file or it will" );
     dgprintf( "create a new file if needed." );