Static initialization of int array from within structure initialization

Question

I'm trying to statically declare and initialize a structure array containing both char and int arrays.

The following example works well.

typedef struct myStruct
{
    char* name;
    uint8_t size;
    uint8_t *value;
}myStruct;

uint8_t struct1_value[] = {0x00, 0x01};
uint8_t struct2_value[] = {0x00, 0x01, 0x03, 0x04};

myStruct myStructArray[] = {
    [0] = {
        .name = "Struct_1",
        .size = 2,
        .value = struct1_value,
    },
    [1] = {
        .name = "Struct_2",
        .size = 4,
        .value = struct2_value,
    },
};

I can't find a syntax that allows to initialize value field directly from myStructArray

I would like to know if there is a way to initialize the value field without having to declare struct1_value and struct2_value variables.

Maybe it's just not possible in pure C but as it's possible to statically initialize a char array, why not with a int array ?

MikeCAT · Accepted Answer · 2020-10-16 14:37:18Z

2

You can use compound literals.

myStruct myStructArray[] = {
    [0] = {
        .name = "Struct_1",
        .size = 2,
        .value = (uint8_t[]){0x00, 0x01},
    },
    [1] = {
        .name = "Struct_2",
        .size = 4,
        .value = (uint8_t[]){0x00, 0x01, 0x03, 0x04},
    },
};

edited Oct 16, 2020 at 14:37

answered Oct 16, 2020 at 14:28

MikeCAT

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4 Comments

MikeCAT Over a year ago

@anastaciu Oh, OP said "The following example works well." but it actually won't...

anastaciu Over a year ago

Yes, recurrent problem :)

Arkaik Over a year ago

@MikeCAT Code fixed, never heard about compound literals before. Thanks

anastaciu Over a year ago

@Arkaik, well, only one thing left to do, UV and accept.

JDługosz · Accepted Answer · 2020-10-16 14:29:32Z

0

value is not an array, but a pointer. You must initialize it by referring to the array that exists elsewhere.

Indeed name works differently because the lexical literal syntax for strings "like this" create an unnamed array of chars.

answered Oct 16, 2020 at 14:29

JDługosz

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