C Tutorial/stdlib.h/realloc

realloc

Item Value Header file stdlib.h Declaration void *realloc(void *ptr, size_t size); Function reallocate memory Parameter If ptr is null, realloc() simply allocates size bytes of memory and returns a pointer. If size is zero, the memory pointed to by ptr is freed.

<source lang="cpp">#include <stdlib.h>

 #include <stdio.h>
 #include <string.h>
 int main(void)
 {
   char *p;
   p = malloc(17);
   if(!p) {
     printf("Allocation Error\n");
     exit(1);
   }
   strcpy(p, "This is 16 chars");
   p = realloc(p, 18);
   if(!p) {
     printf("Allocation Error\n");
     exit(1);
   }
   strcat(p, ".");
   printf(p);
   free(p);
   return 0;
 }</source>