Re: [Linker Error] Unresolved external

You need to link with libpqdll.lib. So far you are just specifying a directory to look for the .lib in  - not actually telling it to do the link. I have no idea how to do that in Borland C++, though. In MSVC you just add the lib file to your project.

(Also, beware that PostgreSQL 7.2.1 is *very* old. I'd strongly suggest you look at something newer. For win32, you can go with either 7.4 on cygwin or 8.0 release candidate on native win32)

//Magnus

> -----Original Message-----
> From: Graf László [mailto:[email protected]] 
> Sent: Monday, December 06, 2004 10:20 AM
> To: [email protected]
> Subject: [pgsql-hackers-win32] [Linker Error] Unresolved external
> 
> Hi all,
> 
> As a novice I installed PostgreSQL 7.2.1 on Win32 and works, 
> Borland C++Builder Enterprise Suite 5.0 (build 12.34) what works too.
> 
> I decided to combine these two programs and develop a simple 
> GUI app to display datas queried from PostgreSQL. I did make 
> the following changes in the project's settings:
> 
> Project->Properties->Directories->Include path += C:\Program 
> Project->Properties->Directories->Files\PostgreSQL\7\include Librariy 
> Project->Properties->Directories->path += C:\Program 
> Project->Properties->Directories->Files\PostgreSQL\7\lib
> 
> (I aded these lines to the project paths).
> 
> Within a brand new BCB project I typed in the simpliest code:
> 
> 
> #include <libpq-fe.h>
> char       *pghost, *pgport, *pgoptions, *pgtty;
> char       *dbName;
> int        nFields, i, j;
> PGconn     *conn;
> PGresult   *res;
> 
> pghost = NULL;              /* host name of the backend server */
> pgport = NULL;              /* port of the backend server */
> pgoptions = NULL;           /* special options to start up the backend
>                                   * server */
> pgtty = NULL;               /* debugging tty for the backend server */
> dbName = "template1";
> 
> /* make a connection to the database */
> conn = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);
> 
> res = PQexec(conn, "BEGIN");
> PQclear(res);
> 
> res = PQexec(conn, "DECLARE mycursor CURSOR FOR SELECT * FROM 
> pg_database"); PQclear(res); res = PQexec(conn, "FETCH ALL in 
> mycursor"); nFields = PQnfields(res); for (i = 0; i < nFields; i++)
>      printf("%-15s", PQfname(res, i));
> printf("\n\n");
> 
> /* next, print out the rows */
> for (i = 0; i < PQntuples(res); i++)
> {
>      for (j = 0; j < nFields; j++)
>          printf("%-15s", PQgetvalue(res, i, j));
>      printf("\n");
> }
> PQclear(res);
> 
> res = PQexec(conn, "CLOSE mycursor");
> PQclear(res);
> 
> /* commit the transaction */
> res = PQexec(conn, "COMMIT");
> PQclear(res);
> 
> /* close the connection to the database and cleanup */ PQfinish(conn);
> 
> When I run the app I got these errors:
> 
> [Linker Error] Unresolved external '_PQconnectdb'
>     referenced from C:\PROGRAM 
> FILES\POSTGRESQL\7\CLIENT\BCB_01\MAIN.OBJ
> [Linker Error] Unresolved external '_PQnfields'
>     referenced from C:\PROGRAM 
> FILES\POSTGRESQL\7\CLIENT\BCB_01\MAIN.OBJ
> [Linker Error] Unresolved external '_PQexec'
>     referenced from C:\PROGRAM 
> FILES\POSTGRESQL\7\CLIENT\BCB_01\MAIN.OBJ
> [Linker Error] Unresolved external '_PQclear'
>     referenced from C:\PROGRAM 
> FILES\POSTGRESQL\7\CLIENT\BCB_01\MAIN.OBJ
> [Linker Error] Unresolved external '_PQfinish'
>     referenced from C:\PROGRAM 
> FILES\POSTGRESQL\7\CLIENT\BCB_01\MAIN.OBJ
> 
> What is wrong? I supose that I miss something to configure.
> 
> Laszlo Graf
> 
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