Обсуждение: help for compiling libpq sample program

"cc -O -o pgsample pgsample.c -L/usr/local/pgsql/lib -lpq" went thru.

Then I did "make pgsample.o".

After that "make pgsample", this process gave me original errors:

pgsample.o: In function `main':
pgsample.o(.text+0x12): undefined reference to `PQconnectdb'
pgsample.o(.text+0x2b): undefined reference to `PQstatus'
pgsample.o(.text+0x5c): undefined reference to `PQerrorMessage'
pgsample.o(.text+0xd0): undefined reference to `PQexec'
pgsample.o(.text+0xe9): undefined reference to `PQresultStatus'
pgsample.o(.text+0x117): undefined reference to `PQclear'
pgsample.o(.text+0x128): undefined reference to `PQfinish'
pgsample.o(.text+0x152): undefined reference to `PQntuples'
pgsample.o(.text+0x17d): undefined reference to `PQgetvalue'
pgsample.o(.text+0x1aa): undefined reference to `PQclear'
pgsample.o(.text+0x1bb): undefined reference to `PQfinish'
collect2: ld returned 1 exit status
make: *** [pgsample] Error 1


Here is my code:

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

int main()
{

   char      state_code[3];
   char      query_string[256];
   PGconn    *conn;
   PGresult  *res;
   int       i;

   conn = PQconnectdb("dbname=webcalendar");

   if (PQstatus(conn) == CONNECTION_BAD)
   {
      fprintf(stderr, "Connection to database failed.\n");
      fprintf(stderr, "%s", PQerrorMessage(conn));
      exit(1);
   }
   printf("Enter a name of the city: ");
   scanf("%2s", state_code);

   sprintf(query_string,
          "SELECT * \
           FROM webcal_entry \
           ");

   res = PQexec(conn, query_string);

   if (PQresultStatus(res) != PGRES_TUPLES_OK)
   {
      fprintf(stderr, "SELECT query failed.\n");
      PQclear(res);
      PQfinish(conn);
      exit(1);
   }

   for (i = 0; i<PQntuples(res); i++)
       printf("%s\n", PQgetvalue(res, i, 0));

   PQclear(res);
   PQfinish(conn);
   return 0;
}

Here is my C program:

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

int main()
{

   char      state_code[3];
   char      query_string[256];
   PGconn    *conn;
   PGresult  *res;
   int       i;

   conn = PQconnectdb("dbname=webcalendar");

   if (PQstatus(conn) == CONNECTION_BAD)
   {
      fprintf(stderr, "Connection to database failed.\n");
      fprintf(stderr, "%s", PQerrorMessage(conn));
      exit(1);
   }
   printf("Enter a name of the city: ");
   scanf("%2s", state_code);

   sprintf(query_string,
          "SELECT * \
           FROM webcal_entry \
           ");

   res = PQexec(conn, query_string);

   if (PQresultStatus(res) != PGRES_TUPLES_OK)
   {
      fprintf(stderr, "SELECT query failed.\n");
      PQclear(res);
      PQfinish(conn);
      exit(1);
   }

   for (i = 0; i<PQntuples(res); i++)
       printf("%s\n", PQgetvalue(res, i, 0));

   PQclear(res);
   PQfinish(conn);
   return 0;
}

Thank you in advance.


--
Best Regards,

Mike
Web Programmer
TKO Systems, Ltd.