I'm trying to initialize an array of structures to all-0's, using the below syntax:
STRUCTA array[MAX] = {0};
However, I'm getting the following warning from gcc :
warning: missing braces around initializer
What am i doing wrong - is there another/better way to do this ?
Using Initializer List. int arr[] = { 1, 1, 1, 1, 1 }; The array will be initialized to 0 if we provide the empty initializer list or just specify 0 in the initializer list.
If you have multiple fields in your struct (for example, an int age ), you can initialize all of them at once using the following: my_data data[] = { [3]. name = "Mike", [2]. age = 40, [1].
Initializer List: To initialize an array in C with the same value, the naive way is to provide an initializer list. We use this with small arrays. int num[5] = {1, 1, 1, 1, 1}; This will initialize the num array with value 1 at all index.
There are two ways to specify initializers for arrays: With C89-style initializers, array elements must be initialized in subscript order. Using designated initializers, which allow you to specify the values of the subscript elements to be initialized, array elements can be initialized in any order.
It the first member of your struct has a scalar type, use
STRUCTA array[MAX] = {{ 0 }};
If the first member of your struct happens to be another struct object, whose first member has scalar type, then you'll have to use
STRUCTA array[MAX] = {{{ 0 }}};
and so on. Basically, you have to open a new level of nested {}
every time you "enter" another nested aggregate (a struct or an array). So in this case as long as the first member of each nested aggregate is also an aggregate, you need to go deeper with {}
.
All these extra braces are only there to avoid the warning. Of course, this is just a harmless warning (in this specific case). You can use a simple { 0 }
and it will work.
Probably the the best way to deal with this is to disable this warning entirely (see @pmg's answer for the right command-line option). Someone working on GCC wasn't thinking clearly. I mean, I understand the value of that warning (and it can indeed be very useful), but breaking the functionality of { 0 }
is unacceptable. { 0 }
should have been given special treatment.
gcc is being a nuisance. It should accept that without warnings.
Try this
STRUCTA array[MAX] = {{0}};
That gcc behaviour can be controlled with the option -Wmissing-braces
or -Wno-missing-braces
.
-Wall
enables this warning; to have -Wall
but not the missing braces, use -Wall -Wno-missing-braces
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