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On 16 Apr 2004, at 17:15, Mark Hamburg wrote:

on 4/16/04 6:22 AM, Edgar Toernig at froese@gmx.de wrote:

The C<->Lua transition is normally cheap.  Not very different from a
function call within Lua.  But what *could* be expensive is lua_pcall.
The problem with lua_pcall is that it uses setjmp/longjmp which
performs a system call on some systems (those which preserve signal
masks).  You could either try _setjmp/_longjmp instead or use lua_call
and catch errors elsewhere (may become difficult with C++).
Additionally, lua_call instead of lua_pcall would remove stack frames
5, 6, and 7 from the above trace.

You could also revise luaD_rawrunprotected and luaD_throw to use C++
exceptions. (Covered previously on this list.) Then Lunar wouldn't need to use pcall to catch any errors since they would be reported just like other
C++ errors.

Mark

P.S. lua_lock and lua_unlock for multithreaded execution become a noticeable
issue in Lua/C and C/Lua transitions.

Thanks to both of you for your suggestions, which I'll both try out -- currently Lua is always run from a single thread in my application, so I leave lua_lock/unlock empty by default.

Ciao,
Dario