#include <stddef.h>

char lang_mem_npd_simple(void){
    char *p = NULL;
    return p[0];              /* 'Null Pointer Dereference' warning issued here */
}

char lang_mem_npd_with_aliasing(int x){
    char *p1 = NULL;
    char *p2;
    char c;

    if (x < 0){
      p2 = "012345678";
    }
    else {
      p2 = p1;                 /* 'Unused Value' warning issued here
                                * - this value of p2 is only used in a statement
                                *   that causes a program crash (via Null Pointer Dereference),
                                *   so CodeSonar considers it unused.
                                */
    }
    c = p2[0];
    return c;                  /* 'Null Pointer Dereference' warning issued here */
}

char * lang_mem_npd_with_malloc(void){
    char *p = malloc(10);
    p[0] = 'X';                /* 'Null Pointer Dereference' warning issued here
                                * only when MALLOC_FAILURE_BEHAVIOR=RETURN_NULL (factory setting)
                                */
    return p;              
}

char *q = malloc(10); /* malloc() can fail and return NULL */
q[0] = 'a';           /* in which case a Null Pointer Dereference occurs here */

char *q = malloc(10); 
if (q){
   /* do something */
   }
else {
   /* do something different */
}