Miscellaneous routines (GNU Compiler Collection (GCC) Internals) (original) (raw)

3.6.2 Split stack functions and variables ¶

Runtime Function: void * __splitstack_find (void *segment_arg, void *sp, size_t len, void **next_segment, void **next_sp, void **initial_sp) ¶

When using -fsplit-stack, this call may be used to iterate over the stack segments. It may be called like this:

void *next_segment = NULL; void *next_sp = NULL; void *initial_sp = NULL; void stack; size_t stack_size; while ((stack = __splitstack_find (next_segment, next_sp, &stack_size, &next_segment, &next_sp, &initial_sp)) != NULL) { / Stack segment starts at stack and is stack_size bytes long. */ }

There is no way to iterate over the stack segments of a different thread. However, what is permitted is for one thread to call this with the segment_arg and sp arguments NULL, to passnext_segment, next_sp, and initial_sp to a different thread, and then to suspend one way or another. A different thread may run the subsequent __splitstack_find iterations. Of course, this will only work if the first thread is suspended while the second thread is calling __splitstack_find. If not, the second thread could be looking at the stack while it is changing, and anything could happen.

Variable: __morestack_segments ¶

Variable: __morestack_current_segment ¶

Variable: __morestack_initial_sp ¶

Internal variables used by the -fsplit-stack implementation.