49 lines
2.4 KiB
Plaintext
49 lines
2.4 KiB
Plaintext
|
test6-execsymbols2
|
||
|
|
|
||
|
|
Try again to allow the module to reference symbols in the executable.
|
||
|
|
But this time, eliminate direct symbol references from the executable
|
||
|
|
to the module, so that the executable can be linked first. I believe
|
||
|
|
this will work ok for win32 and it's closer to how plugins need to work.
|
||
|
|
|
||
|
|
What I think I learned from test5:
|
||
|
|
> DLLs don't allow any symbols to be undefined at link time. So you have to
|
||
|
|
> choose the order of how to build things so that each link is complete.
|
||
|
|
> For a DLL that's used as a shared library, it must be built and linked on
|
||
|
|
> its own (without the program), with symbols exported. This link must be
|
||
|
|
> complete, so it can't depend on pieces from the program. Then, the
|
||
|
|
> program can be linked with the DLL, with the program reading symbols from
|
||
|
|
> the DLL. It can't go both ways.
|
||
|
|
>
|
||
|
|
> For a plugin environment, we want the plugin to be able to call functions
|
||
|
|
> in the main code, without putting every single thing as a function pointer.
|
||
|
|
> So the main executable should be built first, with appropriate symbols
|
||
|
|
> exported, and then the plugin can import those symbols. The main
|
||
|
|
> executable will find symbols in the DLL using lt_dlopen() and lt_dlsym(),
|
||
|
|
> which probably maps to LoadLibrary() and GetProcAddress().
|
||
|
|
|
||
|
|
|
||
|
|
module1.lo: In function `module_init(void)':
|
||
|
|
/home/bryce/bochs-testing/plugin-test/test6-execsymbols2/module1.cc:7: undefined reference to `import stub for register_module(char const *)'
|
||
|
|
|
||
|
|
---------------------
|
||
|
|
ltdl error
|
||
|
|
Program received signal SIGSEGV, Segmentation fault.
|
||
|
|
tryall_dlopen_module (handle=0x78f928, prefix=0x0, dirname=0x0,
|
||
|
|
dlname=0x100d2118 "cygmodule1-0.dll") at ltdl.c:1958
|
||
|
|
1958 if (dirname[dirname_len -1] == '/')
|
||
|
|
Current language: auto; currently c
|
||
|
|
(gdb) where
|
||
|
|
#0 tryall_dlopen_module (handle=0x78f928, prefix=0x0, dirname=0x0,
|
||
|
|
dlname=0x100d2118 "cygmodule1-0.dll") at ltdl.c:1958
|
||
|
|
#1 0x1000249b in find_module (handle=0x78f928, dir=0x0, libdir=0x100d2190
|
||
|
|
"/home/bryce/bochs-testing/plugin-test/test6-ltdlopen/lib",
|
||
|
|
dlname=0x100d2118 "cygmodule1-0.dll", old_name=0x100d2130 "libmodule1.a",
|
||
|
|
installed=0) at ltdl.c:2024
|
||
|
|
#2 0x100035f8 in try_dlopen (phandle=0x78f958,
|
||
|
|
filename=0x78f98c "libmodule1.la") at ltdl.c:2798
|
||
|
|
#3 0x100038a5 in lt_dlopen (filename=0x78f98c "libmodule1.la") at ltdl.c:2893
|
||
|
|
#4 0x10001143 in load_module (fmt=0x100011fc "lib%s.la",
|
||
|
|
name=0x100011f4 "module1") at main.cc:19
|
||
|
|
#5 0x100012bb in main (argc=1, argv=0x100d0e60) at main.cc:46
|
||
|
|
|