Обсуждение: error in code

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error in code

От
Ashok Chauhan
Дата:
****************************
# include <stdio.h>
# include <stdlib.h>
# include <libpq-fe.h>

int main()
{
        PGresult *result;
        PGconn *conn;
        int feild;
        printf("successful");
        conn = PQconnectdb ("ashok");
        result = PQexec (conn, "select * from bill");
        feild = PQntuples (result);
        printf("%d",feild);
        PQclear (result);
        PQfinish (conn);
        printf("hello");
        return 1;


}

I written a code and compile with following command, it complied and
create 'a.out' file but when i run the a.out it give nothing.
command:- "gcc program.c -I /usr/include/pgsql/include -L
/usr/lib/libpq.a -lpq"

plz help me.
Ashok

Re: error in code

От
Stephen Powell
Дата:
On 10 Dec 2003, ashok@kalculate.com wrote:

> I written a code

[...]

Checking for errors is good:

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

int main()
{
        PGresult *result = NULL;
        PGconn *conn = NULL;
        int feild;
        printf("successful");
        conn = PQconnectdb ("ashok");
  if (!conn || CONNECTION_BAD == PQstatus(conn)) {
    fprintf(stderr, "Connection to database failed.\n");
    fprintf(stderr, "%s", PQerrorMessage(conn));
    exit(EXIT_FAILURE);
  }
        result = PQexec (conn, "select * from bill");
  if (!result || PGRES_TUPLES_OK != PQresultStatus(result)) {
    fprintf(stderr, "select command returned no tuples\n");
    fprintf(stderr, "%s", PQerrorMessage(conn));
    exit(EXIT_FAILURE);
  }
        feild = PQntuples (result);
        printf("%d",feild);
        PQclear (result);
        PQfinish (conn);
        printf("hello");
        return EXIT_SUCCESS;
}

> when i run the a.out it give nothing.

Not even "successful" or "hello" from the printfs?

> plz help me.

Download the programmers manual from here <http://www.postgresql.org/docs/>

--
Stephen Powell