How to initialize array in an array of structs?

Question

Let's assume I have a structure defined as:

typedef struct _TStruct {

    uint Values[3];

} TStruct;

Then I define an array of structures:

TStruct Data[3];

How do I correctly initialize the arrays in this array of structures?

The cited dup and [GCC 53119 bug](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119) seems to surface when using `{0}` with missing braces. This question does not appear to be initializing that way. — jww, Feb 19 '17 at 21:13

score 2 · Accepted Answer · edited May 23 '17 at 11:54

2

To correctly initialize an array in an array of structures you need to do the following:

typedef struct _TStruct {

    uint Values[3];

} TStruct;

TStruct Data[3] = {

    {{ 0x86, 0x55, 0x79 }}, {{ 0xaa, 0xbb, 0xcc }}, {{ 0x76, 0x23, 0x24 }}

};

Pay attention to the double braces around every group of values. The additional pair of braces is essential to avoid getting a following gcc error (only when -Wall flag is present, precisely it's "detected" by gcc -Wmissing-braces flag):

warning: missing braces around initializer

Note:

Usage of double braces {{ }} does not change the layout of data in memory
This warning does not appear on MS Visual Studio C++ compiler

See also:

How to repair warning: missing braces around initializer?

GCC Bug 53319

edited May 23 '17 at 11:54

Community

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answered Feb 19 '17 at 20:46

Peter Cerba

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Your Q & A is a duplicate of the linked Q & A you provided. Why posting that then? – Jean-François Fabre Feb 19 '17 at 20:48
@Jean-FrançoisFabre There was no question/answer on SO showing how to initialize array in an array of structs – Peter Cerba Feb 19 '17 at 20:49
Note that omitting braces is also correct according to the C Standard. The extra bracing is only "required" to work around a compiler defect. – M.M Mar 22 '17 at 01:51

How to initialize array in an array of structs?

1 Answers1