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tal/stack
stack of tal contexts (inspired by talloc_stack)
Delio Brignoli <[email protected]>
Implement a stack of tal contexts. A new (empty) context is pushed on top of the stack using tal_newframe and it is popped/freed using tal_free(). tal_curframe() can be used to get the stack's top context.
tal_stack can be used to implement per-function temporary allocation context to help mitigating memory leaks, but unlike the plain tal approach it does not require the caller to pass a destination context for returning allocated values. Instead, allocated values are moved to the parent context using tal_steal(tal_parent(tmp_ctx), ptr).
#include <assert.h>
#include <ccan/tal/stack/stack.h>
static int *do_work(void)
{
int *retval = NULL;
tal_t *tmp_ctx = tal_newframe();
int *val = talz(tmp_ctx, int);
assert(val != NULL);
// ... do something with val ...
if (retval >= 0) {
// steal to parent cxt so it survives tal_free()
tal_steal(tal_parent(tmp_ctx), val);
retval = val;
}
tal_free(tmp_ctx);
return retval;
}
int main(void)
{
tal_t *tmp_ctx = tal_newframe();
int *val = do_work();
if (val) {
// ... do something with val ...
}
// val is eventually freed
tal_free(tmp_ctx);
return 0;
}
BSD-MIT