greenlet source code -- g_save

stack_copy

stack_copy + stack_saved

static int g_save(PyGreenlet* g, char* stop)
{
/* Save more of g's stack into the heap -- at least up to 'stop'  */

intptr_t sz1 = g->stack_saved;
intptr_t sz2 = stop - g->stack_start;
assert(g->stack_start != NULL);
if (sz2 > sz1) {
char* c = (char*)PyMem_Realloc(g->stack_copy, sz2);
if (!c) {
PyErr_NoMemory();
return -1;
}
memcpy(c+sz1, g->stack_start+sz1, sz2-sz1);
g->stack_copy = c;
g->stack_saved = sz2;
}
return 0;
}