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On Dec 11, 11:36*am, "Borneq" <bor...@antyspam.hidden.pl> wrote:

> Where I can find setjmp,longjmp, sigsetjmp implementation? In GCC source I
> can't find.

Plauger's Library Book discusses setjmp and longjmp implementation

http://www.amazon.co.uk/Standard-C-L...dp/0131315099/

and its great book to read anyway

Nobody <> writes:

> On Wed, 12 Dec 2012 15:19:57 +0100, Johann Klammer wrote:
>
>> Doesn't the whole machine state have to be
>> saved/restored(registers/Fp/SSE/flags etc)?
>
> No.
>
>> What if the calling function was using some regs for local vars etc ?!...
>
> 7.13.2.1p3:
>
> All accessible objects have values as of the time longjmp was
> called, except that the values of objects of automatic storage
> duration that are local to the function containing the
> invocation of the corresponding setjmp macro that do not have
> volatile-qualified type and have been changed between the
> setjmp invocation and longjmp call are indeterminate.
>
> gcc will warn about such cases with e.g.:
>
> warning: variable 'foo' might be clobbered by 'longjmp' or 'vfork'

A herring was never redder.

> Typically, only the "essential" registers (program counter, stack pointer,
> frame pointer) are preserved. Registers holding local variables or
> intermediate results aren't required to be preserved (and usually aren't).
> [snip unrelated]

This is nonsense. Any register holding a live value at the time
of the call to setjmp must be preserved, and restored by longjmp.
Most commonly that will be most or all the registers.