Re: [PATCH 1/2] d3d10: Add a function to initialize the null variables.

[Henri Verbeet]

2009/12/31 Rico Schüller :
> +static struct d3d10_effect_variable null_local_buffer = {0};
> +static struct d3d10_effect_variable null_variable = {0};
> +static struct d3d10_effect_variable null_scalar_variable = {0};
> +static struct d3d10_effect_variable null_vector_variable = {0};
> +static struct d3d10_effect_variable null_matrix_variable = {0};
> +static struct d3d10_effect_variable null_string_variable = {0};
> +static struct d3d10_effect_variable null_shader_resource_variable = {0};
> +static struct d3d10_effect_variable null_render_target_view_variable = {0};
> +static struct d3d10_effect_variable null_depth_stencil_view_variable = {0};
> +static struct d3d10_effect_variable null_shader_variable = {0};
> +static struct d3d10_effect_variable null_blend_variable = {0};
> +static struct d3d10_effect_variable null_depth_stencil_variable = {0};
> +static struct d3d10_effect_variable null_rasterizer_variable = {0};
> +static struct d3d10_effect_variable null_sampler_variable = {0};

This doesn't hurt (much), but since a lot of people seem to be unaware
of this I think it's worth mentioning again. Global variables as well
as static (local) variables are initialized to 0 / NULL by default.

The way this works in the language spec is that objects with static
storage duration (i.e. the entire lifetime of the program/module) are
initialized to 0 / NULL unless explicitly initialized. In practice
that means global and static variables (but note that static on a
global variable or function has a different meaning from static on a
local variable).
> +static void d3d10_null_effect_variable_init(struct d3d10_effect_variable *v, struct ID3D10EffectVariableVtbl *vtbl)
> +{
> - v->vtbl = vtbl;
> - v->buffer = &null_local_buffer;
> - v->effect = NULL;
> - v->name = NULL;
> - v->semantic = NULL;
> - v->buffer_offset = 0;
> - v->annotation_count = 0;
> - v->flag = 0;
> - v->data_size = 0;
> - v->type = &null_type;
> - v->elements = NULL;
> - v->members = NULL;
> - v->annotations = NULL;
>
> +}

Most of these are redundant, since the variable will be already
initialized with zeroes.