Re: Problem of Magic Block in Postgres 8.2

Pei He <hepeimail(at)gmail(dot)com> wrote:

> The extension functions was developed by C++ mixed with C.
> ERROR: incompatible library
> "/home/hepei/bin/Chameleon/lib/libspgist_trie.so": missing magic block
> HINT: Extension libraries are required to use the PG_MODULE_MAGIC macro.

You can use extern "C" blocks for PG_MODULE_MAGIC, PG_FUNCTION_INFO_V1,
and function declarations:

extern "C"
{
#include "postgres.h"
#include "fmgr.h"

PG_MODULE_MAGIC;

PG_FUNCTION_INFO_V1(your_function);
extern Datum your_function(PG_FUNCTION_ARGS);
}

However, you should very carefully use C++ exceptions and destructors
in your module because PostgreSQL uses siglongjmp; C++ unwind semantics
don't work on postgres' errors. You cannot use those C++ features and
postgres' APIs together.

Regards,
---
Takahiro Itagaki
NTT Open Source Software Center