diff --git a/qpms/apps/hexlattice_ewald_altin.c b/qpms/apps/hexlattice_ewald_altin.c
index a9acd89..590406f 100644
--- a/qpms/apps/hexlattice_ewald_altin.c
+++ b/qpms/apps/hexlattice_ewald_altin.c
@@ -152,6 +152,7 @@ int main (int argc, char **argv) {
   const double MAXR_REAL = 100 * LATTICE_H;
   const double MAXR_K = 100 * INVLATTICE_A;
 
+  if (argc < 2) abort();
 
   char *omegastr = argv[1];
   // char *kfile = argv[2]; // not used;, will be read from stdin