p_open
if (fetched_loader->p_open != NULL && (loader_ctx = fetched_loader->p_open(provctx, uri)) != NULL && !loader_set_params(fetched_loader, loader_ctx, params, propq)) {
OSSL_FUNC_store_open_fn *p_open;
if (loader->p_open == NULL)
loader->p_open = OSSL_FUNC_store_open(fns);
if ((loader->p_open == NULL && loader->p_attach == NULL)
int p_open(const char *, pid_t *);
p_open(prog, rpd)
pipedesc_w = p_open(prog, &procdesc);