setjmp/longjmp's enviroment

setjmp/longjmp's enviroment

[rinku rathore]

Hello All,
I wanted to know about "setjmp/longjmp",
What I understood is setjmp will save the current
environment of the program but cann't get much about
hte enviroment can anybody give me detail about the
environment.I get that it will save the fp,stack
pointer, program counter what else it will store.

please help me,
thanx in advance,
Regards,
Rinku Rathore.


		
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Re: setjmp/longjmp's enviroment

[Glynn Clements]

rinku rathore wrote:

> I wanted to know about "setjmp/longjmp",
> What I understood is setjmp will save the current
> environment of the program but cann't get much about
> hte enviroment can anybody give me detail about the
> environment.I get that it will save the fp,stack
> pointer, program counter what else it will store.

On x86, setjmp() stores the registers: EBX, ESI, EDI, EBP, ESP, EIP;
sigsetjmp() may additionally save the signal mask. It doesn't save the
FPU state.

Essentially, it saves the registers which need to be preserved across
a function call, so that a return from setjmp() via longjmp() appears
the same as a return from a normal function call (i.e. EAX, ECX and
EDX may contain garbage; the others must be preserved).

-- 
Glynn Clements <glynn@gclements.plus.com>