C struct hack at work -


is how 1 can use the "extra" memory allocated while using c struct hack?

questions:

i have c struct hack implementation below. question how can use "extra" memory have allocated hack. can please give me example on using memory ?

#include<stdio.h> #include<stdlib.h>  int main() {      struct mystruct {          int len;         char chararray[1];      };      struct mystruct *ptr = malloc(sizeof(struct mystruct) + 10 - 1);     ptr->len=10;       ptr->chararray[0] = 'a';     ptr->chararray[1] = 'b';     ptr->chararray[2] = 'c';     ptr->chararray[3] = 'd';     ptr->chararray[4] = 'e';     ptr->chararray[5] = 'f';     ptr->chararray[6] = 'g';     ptr->chararray[7] = 'h';     ptr->chararray[8] = 'i';     ptr->chararray[9] = 'j';   }

yes, (and was) standard way in c create , process variably-sized struct.

that example bit verbose. programmers handle more deftly:

struct mystruct {         int len;         char chararray[1];  // compilers allow [0] here     };     char *msg = "abcdefghi";     int n = strlen (msg);      struct mystruct *ptr = malloc(sizeof(struct mystruct) + n + 1);      ptr->len = n;     strcpy (ptr->chararray, msg); }

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