Re: [pclasses-devel] SOLVED: IOManager not finding protocol handlers

[Christian P. <cp...@se...>]

Am Dienstag 21 Dezember 2004 00:51 schrieb stephan beal:
> You're not gonna believe what it was:
>
> Last weekend i reported that i had to link directly against psq_mysql.so
> to avoid an undef'd BigInt symbol. THAT is what caused the IOManager to
> not find the factories. i can't explain it, but i can reproduce it:
> removing that .so from my linking fixes the problem, adding it back on
> breaks it again.

It's clear to me. Libraries linked against your app binary export their 
symbols "global". Plugins are loaded without overwriting 
"global" (~RTLD_GLOBAL) bindings.
When shared libraries are loaded, colliding symbols are not rebound.
So the actual problem is that your binary has a global symbol "P_plugins",
and every plugin you dynamically load also has this symbol exported, which not 
gets overwritten.

> WEIRD...
>
> My client fails with these link args:
> -ls11n -lpcore -lpcrypto -lpio -lpnet -lpsql
> -lps11n /home/stephan/cvs/inst/lib/pclasses/psql_mysql.so
>
> piomanager.cpp:40 : IOManager loading plugins from .
> [/home/stephan/cvs/inst/lib/pclasses].
> piomanager.cpp:50 : file??? 0
> piomanager.cpp:51 : ftp??? 0
> piomanager.cpp:52 : http??? 0
> piomanager.cpp:127:P::IOHandler* P::IOManager::findCreateHandler(const
> std::string&): No handler for protocol 'http' found.
>
> But works with these:
> -ls11n -lpcore -lpcrypto -lpio -lpnet -lpsql -lps11n
>
> piomanager.cpp:40 : IOManager loading plugins from .
> [/home/stephan/cvs/inst/lib/pclasses].
> piomanager.cpp:50 : file??? 0x808b860
> piomanager.cpp:51 : ftp??? 0x808fab8
> piomanager.cpp:52 : http??? 0x808fb08
> test.cpp:75 : Buffered 1042 bytes from [http://localhost/P.s11n].