svn commit: r295768 - head/usr.sbin/iostat

[Dimitry Andric]

On 22 Feb 2016, at 10:56, David Chisnall <theraven at FreeBSD.org> wrote:
> 
> On 19 Feb 2016, at 23:23, Dimitry Andric <dim at FreeBSD.org> wrote:
>> 
>> This warning is only produced when you use -Wall -W, and then initialize
>> structs partially, i.e. you initialize some fields but not others.  I
>> think this is a quite reasonable warning for a high warning level.
> 
> The warning is annoying in many ways.  You ought to be able to zero initialise any struct with {0}, but clang objects if you do this and requires every field to be filled in.  This warning really shouldn’t be enabled with -Wall, because it has too hight a false positive rate.

It isn't, it is in -W (a.k.a -Wextra).  But gcc also warns in this case.  E.g. if I use this example:

struct foo {
	int i;
	int j;
} bar[] = {
	{ 42 },
	{ 43 }
};

I get the following warnings from gcc -Wextra:

$ gcc -Wextra -c initializers.c
initializers.c:5:2: warning: missing initializer for field 'j' of 'struct foo' [-Wmissing-field-initializers]
  { 42 },
  ^
initializers.c:3:6: note: 'j' declared here
  int j;
      ^
initializers.c:6:2: warning: missing initializer for field 'j' of 'struct foo' [-Wmissing-field-initializers]
  { 43 }
  ^
initializers.c:3:6: note: 'j' declared here
  int j;
      ^

Note that the warnings disappear if C99 initializers are used.

-Dimitry

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