Segmentation fault

Hi, i am testing PostgreSQL and have already run into questions...

Can someone explain why i don´t get a error message the second time i
run this program saying "TABLE slask ALREADY EXISTS", instead i get
"Segmentation fault (core dumped)"

Thanks !

/Stefan

#include <stdio.h>
#include "libpq-fe.h"

void exit_nicely(PGconn* conn)
{
  PQfinish(conn);
  exit(1);
}

main()
{
  char *pghost, *pgport, *pgoptions, *pgtty;
  char* dbName;

  PGconn* conn;
  PGresult* res;

  pghost = NULL;
  pgport = NULL;
  pgoptions = NULL;
  pgtty = NULL;
  dbName = "test";

  conn = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);

  if (PQstatus(conn) == CONNECTION_BAD)
  {
    fprintf(stderr,"%s",PQerrorMessage(conn));
    exit_nicely(conn);
  }

  // create the table
  res = PQexec(conn, "CREATE TABLE slask(name char(20), phone
char(10))");
  if (PQresultStatus(res) != PGRES_COMMAND_OK)
  {
    fprintf(stderr,"CREATE TABLE slask failed !");
    PQclear(res);
    exit_nicely(conn);
  }
  PQclear(res);

  PQfinish(conn);
}