Error: linker: Undefined symbols for architecture x86_64:

[daniel_sap]

Hi,

I created a simple library, with just one function.
After compiling it a libsimple.dylib file was generated.
I created a test lib project where I import the function.
Also, copied the dylan file in the project's folder, as well to x86_64-darwin

When compiling the project I received this error

Code: Text  [Select][+][-]

1. Compile Project, Target: Libtest: Exit code 1, Errors: 4, Hints: 3
2. Hint: Start of reading config file /Users/julian/FpcUpDeluxe/fpcupdeluxe/fpc/bin/x86_64-darwin/fpc.cfg
3. Hint: End of reading config file /Users/julian/FpcUpDeluxe/fpcupdeluxe/fpc/bin/x86_64-darwin/fpc.cfg
4. Verbose: Free Pascal Compiler version 3.3.1-r48994 [2021/03/17] for x86_64
5. Verbose: Copyright (c) 1993-2021 by Florian Klaempfl and others
6. Verbose: Target OS: Darwin for x86_64
7. Verbose: Compiling Libtest.lpr
8. Verbose: Compiling mainform.pas
9. Verbose: Compiling simple.pas
10. Verbose: Assembling simple
11. mainform.pas(19,28) Verbose: Parameter "Sender" not used
12. mainform.pas(34,3) Hint: Unit "simple" not used in MainForm
13. Verbose: Assembling mainform
14. Libtest.lpr(13,20) Verbose: Unit "simple" not used in Libtest
15. Verbose: Assembling libtest
16. Verbose: Compiling resource /Users/julian/Project/ProjectL/Applications/Research/Libtest/lib/x86_64-darwin/Libtest.or
17. Verbose: Linking /Users/julian/Project/ProjectL/Applications/Research/Libtest/Libtest
18. Error: linker: Undefined symbols for architecture x86_64:
19. Error: linker:   "_sum2int", referenced from:
20. Debug:   "_sum2int", referenced from:
21. Debug:       _SIMPLE_$$_SUM2INT$LONGINT$LONGINT$$LONGINT in simple.o
22. Error: ld: symbol(s) not found for architecture x86_64
23. An error occurred while linking
24. Error: Error while linking
25. Verbose: There were 1 errors compiling module, stopping
26. Verbose: Compilation aborted
27. Verbose: /Users/julian/FpcUpDeluxe/fpcupdeluxe/fpc/bin/x86_64-darwin/ppcx64 returned an error exitcode
28.  

the import code looks like this

Code: Pascal  [Select][+][-]

1. unit simple;
2.  
3. {$mode ObjFPC}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils;
9.  
10. const
11.   lib_path = '/Users/julian/Project/ProjectL/Libraries/simplelib/';
12.   simple_lib = 'simple.dylib';
13.   {$linklib simple.dylib}
14.  
15. function sum2int(val1, val2: Integer): Integer; {$IFNDEF WINDOWS}cdecl{$ELSE}stdcall{$ENDIF};
16. {$EXTERNALSYM sum2int}
17.  
18. implementation
19.  
20. function sum2int(val1, val2: Integer): Integer; {$IFNDEF WINDOWS}cdecl{$ELSE}stdcall{$ENDIF};
21.     external simple_lib name 'sum2int';
22.  
23. end.
24.  

In the code I tried also with
simple_lib = 'simple';
simple_lib = 'simple.dylib';
simple_lib = 'libsimple.dylib';

I searched the web and the forum but the articles I read didn't help me much.
May be you can give some more information about the error.

[trev]

Compare what you've done with my Wiki example in the macOS Dynamic Libraries article.

[daniel_sap]

Thank you @trev for helping again and for pointing me to the wiki example and that you wrote this example.
I'll check the differences.

[daniel_sap]

Issue solved, it is completely different syntax compared to Delphi.

After reading the Wiki I choose dynamic linking of the library (not the static).
I edited the code as the second example for dynamic linking.

Code: Pascal  [Select][+][-]

1. unit simple;
2. {$linklib libsimple}
3. {$mode ObjFPC}{$H+}
4.  
5. interface
6.  
7. function sum2ints(val1, val2: Integer): Integer; {$IFDEF WINDOWS}stdcall{$ELSE}cdecl{$ENDIF}; external;
8.  
9. implementation
10.  
11. end.
12.  

I like how simple is the import of library functions. It is simple like that in Java. In Delphi it looks unnecessary complicated.

[trev]

Good to hear you solved it. It's always easy when you know how  The Wiki is a great resource that is often overlooked.