[fpc-devel] Crosscompiling win towards darwin

Jonas Maebe jonas.maebe at elis.ugent.be
Mon Nov 21 09:35:49 CET 2016

Alfred wrote:
> With the osxcross tools, cross-compilation of non-LCL programs from
> Windows to Darwin is now successful.
> When compiling with LCL, one final error keeps popping up:
> Error: linker: Undefined symbols for architecture i386:
> Error: linker:   "FPC_RESSYMBOL", referenced from:
> Debug:   "FPC_RESSYMBOL", referenced from:
> Debug:       FPC_RESLOCATION in project1.o
> ld: symbol(s) not found for architecture i386

FPC_RESSYMBOL is created by the resource writer (fpcres) in the object
file generated from the resources.

You shouldn't need a complete Lazarus program to test this,
tests/test/units/system/tres.pp should be sufficient.

If you compile that test with -va, you should see something like this:

[1.113] Calling resource compiler "/usr/local/bin/fpcres" with "-o
tres.or -a i386 -s all -of mach-o -v '@tres.reslst'" as command line

In particular, the "-of macho-o" is important. There should be a tres.or
file afterwards that defines FPC_RESSYMBOL. If your osxcross tools
include a copy of the nm binary, you can use that to check: "nm tres.or"
should print something like "00000000 S FPC_RESSYMBOL" (otherwise copy
the file to a Mac and run nm there). On a Mac, you can also use "file
tres.or" to verify that it is actually an i386 Mach-O object file.

This tres.or file should also be linked into the generated binary.
Compile with -a -s and check whether tres.or appears in link.res and/or
in the command line when calling the linker from ppas.bat. Run the
generated ppas.bat file to see whether the linker prints any errors that
Lazarus or the compiler hid.


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