Is empty array in the end of the structure a C standard? -

i have noticed empty array in end of structure used in open source projects:

typedef struct {     ......     void *arr[]; } a;

i want know c standard? or ok gcc compiler?

as of c99, c standard. pre-c99 compilers may not support it. old approach declare 1-element array, , adjust allocation size that.

new way:

typedef struct {     ......     void *arr[]; } a;    int slots = 3; a* mya = malloc(sizeof(a) + slots*sizeof(void*)); mya->arr[2] = foo;

old way:

typedef struct {     ......     void *arr[1]; } a;    int slots = 3; a* mya = malloc(sizeof(a) + (slots-1)*sizeof(void*)); mya->arr[2] = foo;

Cap