mysql_real_connect() produces link errors
lazarus / 16-Databases

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mbohn · 2010-04-12 13:19

OSX 10.6.3
fpc 2.4.0
console app (not using ide)
MySQL 5.1.45 (on client)
MySQL 5.1.44 (on server)

stripped down test code:
Code: [Select]//console app to test connection to a MySQL database
//  using fpc 2.4.0

program TestMySQL; 
{$mode objfpc}{$H+}
uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, SysUtils,  mysql50;

var HostName,UserName,Password,DataBaseName:pchar;
    alloc,sock:PMySQL;

begin
  writeln('');
  writeln('starting TestMySQL');

  HostName:='...';
  UserName:='...';
  Password:='...';
  DataBaseName:='...';

  alloc:=mysql_init(PMYSQL(@qmysql));
 
(*  function prototype from mysql.inc:
  function mysql_real_connect(mysql:PMYSQL; host:Pchar; user:Pchar;
passwd:Pchar; db:Pchar;
               port:cuint; unix_socket:Pchar;
clientflag:culong):PMYSQL;extdecl;external mysqllib name
'mysql_real_connect';
*)

//but then the next line produces link errors:
  sock:=mysql_real_connect(alloc,hostname,username,password,databasena
me,0,nil,0);

mysql_close(sock);
end.


result from compile/link:
Code: [Select]fpc project3.lpr
Free Pascal Compiler version 2.4.0 [2009/12/20] for i386
Copyright (c) 1993-2009 by Florian Klaempfl
Target OS: Darwin for i386
Compiling project3.lpr
Assembling testmysql
Linking project3
Undefined symbols:
  "_mysql_real_connect", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_fetch_row", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_query", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_close", referenced from:
      _PASCALMAIN in project3.o
      _PASCALMAIN in project3.o
      _PASCALMAIN in project3.o
      _PASCALMAIN in project3.o
  "_mysql_init", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_num_rows", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_select_db", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_store_result", referenced from:
      _PASCALMAIN in project3.o
  "_mysql_refresh", referenced from:
      _MYSQL50_MYSQL_RELOAD$PMYSQL$$LONGINT in mysql50.o
ld: symbol(s) not found
An error occurred while linking
Error: Error while linking
Fatal: There were 1 errors compiling module, stopping
Fatal: Compilation aborted
Error: /usr/local/bin/ppc386 returned an error exitcode (normal if you
did not specify a source file to be compiled)
Please note that in working with mysql3 I was able to connect with my
db but not able to perform other mysql functions -- I suppose due to
incompatibilities between 3 and 5.

Thanks for any suggestions.

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mbohn · 2010-04-13 18:14

I have stripped down further my test case:


Code: [Select]//console app to test connection to a MySQL database
//  using fpc 2.4.0

program TestMySQL; 
{$mode objfpc}{$H+}
uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, SysUtils,  mysql50dyn;

var alloc:PMySQL;
    qmysql:Mysql_Res;
   
begin
  alloc:=mysql_init(PMYSQL(@qmysql));
end.
This one compiles and links ok but produces an "Illegal Instruction"
error on run.