ALTSTACK
Syntax
ALTSTACK [on|off]
Variable
VT_ALTSTACK
Description
Handling segfaults due to a stack overflow requires that the signal handler runs
on an alternative stack, otherwise it will just segfault again, causing the
process to terminate.
Because installing an alternative signal handler affects application behavior, it
is normally not done. If it is known to work, it is enabled only for MPI
correctness checking.