Index: trunk/Ohana/src/opihi/lib.shell/BufferOps.c
===================================================================
--- trunk/Ohana/src/opihi/lib.shell/BufferOps.c	(revision 38062)
+++ trunk/Ohana/src/opihi/lib.shell/BufferOps.c	(revision 39233)
@@ -92,9 +92,12 @@
   gfits_free_matrix (&buf[0].matrix);
   gfits_free_header (&buf[0].header);
-  CreateBuffer (buf, Nx, Ny, bitpix, bzero, bscale);
+  if (!CreateBuffer (buf, Nx, Ny, bitpix, bzero, bscale)) return FALSE;
   return TRUE;
 }
 
 int CreateBuffer (Buffer *buf, int Nx, int Ny, int bitpix, float bzero, float bscale) {
+
+  if (Nx < 0) { gprint (GP_ERR, "invalid negative matrix size Nx : %d\n", Nx);  return FALSE; }
+  if (Ny < 0) { gprint (GP_ERR, "invalid negative matrix size Ny : %d\n", Ny);  return FALSE; }
 
   /* store the default output values */
@@ -123,4 +126,8 @@
 // buffer[x + Nx*y + Nx*Ny*z + ...]
 int CreateBuffer3D (Buffer *buf, int Nx, int Ny, int Nz, int bitpix, float bzero, float bscale) {
+
+  if (Nx < 0) { gprint (GP_ERR, "invalid negative matrix size Nx : %d\n", Nx);  return FALSE; }
+  if (Ny < 0) { gprint (GP_ERR, "invalid negative matrix size Ny : %d\n", Ny);  return FALSE; }
+  if (Nz < 0) { gprint (GP_ERR, "invalid negative matrix size Nz : %d\n", Nz);  return FALSE; }
 
   /* store the default output values */