Synopsis

Do not modify objects with temporary lifetime

Enabled by default

Yes

Severity/Certainty

Low/Medium

Full description

If a function call returns by value a struct or union containing an array, do not modify those arrays within the expression containing the function call. Do not access an array returned by a function after the next sequence point or after the evaluation of the containing full expression or full declarator ends.

Coding standards

Code examples

The following code example fails the check and will give a warning:

int printf(const char *a, ...);

struct my_struct { char str[8]; };

struct my_struct get_new_struct(void) {
    struct my_struct a = { "AAAAAAA" };
    return a;
}

void example(void) {
    printf("%s\n", get_new_struct().str);
}

The following code example passes the check and will not give a warning about this issue:

int printf(const char *a, ...);

struct my_struct { char str[8]; };

struct my_struct get_new_struct(void) {
    struct my_struct a = { "AAAAAAA" };
    return a;
}

void example(void) {
    struct my_struct s = get_new_struct();
    printf("%s\n", s.str);
}