[stunnel-users] RE: --with-threads=ucontext portability

Miloslav Trmac mitr at redhat.com
Tue Jan 31 16:05:19 CET 2006

Michal Trojnara wrote:
> What about the number of arguments?  Why isn't "1" correct?
Assume the traditional way of passing arguments on stack, with "int"
naturally aligned.  Then makecontext does something like this:
- set stack pointer to "top" - argc * sizeof(int)
- copy argc * sizeof (int) bytes from makecontext() arguments to stack
- set up the rest of the frame

If sizeof (void *) > sizeof (int), which happens on 64-bit platforms,
the above doesn't copy the whole value of the pointer when argc == 1.

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