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+---- Thread: Rule 11.6.1 - Variables initialized via output-parameter? (/showthread.php?tid=1748)
Rule 11.6.1 - Variables initialized via output-parameter? - cgpzs - 02-09-2025
Hi,
Consider the following example:
Code:
// external_c_api.h
enum error_t
{
// ...
};
enum foo_t
{
foo_A = 1,
foo_B = 2
};
error_t externalCApi(foo_t*);
// main.cpp
void f()
{
foo_t x;
error_t error = externalCApi(&x);
}How would one apply 11.6.1 in this case? It's not possible to avoid the two-step initialization process. There may not even be a "sensible default" to give to `x` before giving it the "real" value (and MISRA explicitly discourages this pattern). In particular, doing "foo_t x{};" leads to zero initialization, but there is no enumerator with the value 0.
Thanks!
RE: Rule 11.6.1 - Variables initialized via output-parameter? - misra cpp - 19-09-2025
11.6.1 is only advisory for precisely this reason, there are cases when it its not possible to initialise to a 'sensible' state.
Note that this rule only cares about variables being initialised, it doesn't care if the value is overwritten before being read, though another rule may fire on that.