Question

How to dynamically allocate a struct that represent an array of bytes in C

Answer 1

#include <stdio.h>
#include <stdlib.h>

typedef struct {
    unsigned int length;
    unsigned char data[];
} SArray;

int main(void) {
   
    SArray* arr;
    unsigned int len = 10;

    arr = malloc((sizeof *arr) + sizeof(unsigned char) * len);
    arr->length = len;

    for (int i = 0; i < len; i++) {
        arr->data[i] = 1;
    }

    for (int i = 0; i < len; i++) {
        printf("%2d", arr->data[i]);
    }

    free(arr);

    return 0;
}




/*
run:

 1 1 1 1 1 1 1 1 1 1

*/

 

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