demo.c

#include <stdio.h>
#include <pgsql/libpq-fe.h>

main () 
{
   FILE *fh;
   PGconn *conn;
   int i, row, col, rc, nrows, ncols;
   char * dbName = "gnc_bogus";
   PGresult *result;

   conn = PQsetdbLogin (NULL, NULL, NULL, NULL, dbName, NULL, NULL);

   if (CONNECTION_BAD == PQstatus(conn))
   {
      printf("Fatal Error: Connection to database '%s' failed:\n",
             dbName ? dbName : "(null)");
      printf("\t%s", PQerrorMessage(conn));
      PQfinish (conn);
      exit (1);
   }

   fh = fopen("/tmp/pgsql.trace","w");
   PQtrace(conn, fh);

   rc = PQsendQuery (conn, "SELECT * FROM gncAccount;");
   if (!rc) 
   {
      printf("Fatal Error: send query failed:\n");
      printf("\t%s", PQerrorMessage(conn));
      PQfinish (conn);
      exit (1);
   }


   i = 0;
   do {
      ExecStatusType status;
      int iacc, idesc;

      result = PQgetResult(conn);
      if (!result) break;
 
      status = PQresultStatus(result);
      
      if ((PGRES_COMMAND_OK != status) && 
          (PGRES_TUPLES_OK  != status)) 
      {
         printf ("Error: failed to get result to query\n");
         PQclear(result);
         PQfinish (conn);
         exit (2);
      }
      nrows = PQntuples (result);
      ncols = PQnfields(result);
      printf ("Info: query result %d has %d rows and %d cols\n", 
              i, nrows, ncols);

      iacc = PQfnumber (result, "accountName");
      idesc = PQfnumber (result, "description");

     printf ("accountName ===   description\n");
      for (row=0; row<nrows; row++) {
          printf ("%s ==== %s\n",
                  PQgetvalue(result, row, iacc),
                  PQgetvalue(result, row, idesc));
      }

      i++;
   } while (result);

   PQfinish (conn);
}

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