Synopsis

A function pointer is used in an invalid context.

Enabled by default

Yes

Severity/Certainty

Low/High

Full description

A function pointer is used in an invalid context. It is an error to use a function pointer to do anything other than calling the function being pointed to, comparing the function pointer to another pointer using != or ==, passing the function pointer to a function, returning the function pointer from a function, or storing the function pointer in a data structure. Misusing a function pointer might result in erroneous behavior, and in junk data being interpreted as instructions and being executed as such.

Coding standards

Code examples

The following code example fails the check and will give a warning:

/* declare a function */
int foo(int x, int y){
  return x+y;
}

#pragma diag_suppress=Pa153

int foo2(int x, int y) {

  if (foo)
    return (foo)(x,y);

  if (foo < foo2)
    return (foo)(x,y);
return 0;
}

The following code example passes the check and will not give a warning about this issue:

typedef int (*fptr)(int,int);

int f_add(int x, int y){
  return x+y;

}

int f_sub(int x, int y){
  return x-y;
}


int foo(int opcode, int x, int y){
  
  fptr farray[2];
  farray[0] = f_add;
  farray[1] = f_sub;

  return (farray[opcode])(x,y);

}

int foo2(fptr f1, fptr f2){

  if (f1 == f2)
    return 1;
  else
    return 0;

}