[Bug c++/61489] Wrong warning with -Wmissing-field-initializers.

["redi at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61489

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Deniz Bahadir from comment #0)
> When compiling the following code (in C++11 mode) with
> -Wmissing-field-initializers then almost all attempts to initialize
> "sockaddr_in" result in compiler-warnings about uninitialized field-members.
> However, as far as I understand, almost all initializations should be fine
> and zero-initialize (?) all struct-members and the compiler-warnings should
> therefore not occur.

But that's exactly the situation -Wmissing-field-initializers is designed to
warn about, so the warning is not wrong.


> 
> 
> <code>
> // Compile this code with: g++ -std=c++11 -Wmissing-field-initializers
> bug.cpp
> 
> #include <netinet/in.h>
> 
> int main()
> {
>     struct sockaddr_in addr0;      // No warning. But really
> zero-initialized?

No, uninitialized.

>     //struct sockaddr_in addr1();  // No warning, but a function-declaration.


>     struct sockaddr_in addr2 = {};    // In C++: Warning about all members.

I think it shouldn't warn for an empty braced-init-list, as that has special
meaning in C++11.

>                                       // In C: Warning about first member.

It's not valid in C, you always need at least one initializer.


>     struct sockaddr_in addr3 = {0};   // In C++: Warning about all members
>                                       //         except the first one.
>     struct sockaddr_in addr4 = {0,};  // Same here.

That's exactly what the warning is designed to warn about.

> #ifdef __cplusplus
>     struct sockaddr_in addr5 = sockaddr_in();  // No warning and (probably)
>                                                // zero-initialized.

Definitely zero-initialized.