C++ Short-Circuit for IF-Statments and While-Loops

Question

I asked myself if short-circuiting in C++ AND C is possible with the following if-condition:

uvc_frame_t *frame = ...; //receive a new frame

if(frame != NULL && frame->data != NULL) cout << "Data read";
    else cout << "Either frame was NULL or no data was read!";

I'm not sure wheter this statement could throw an segmentation fault, because if frame is NULL then you can't check for frame->data!

• And is it the same for while loop conditions?

  while(frame == NULL && frame->data == NULL)
  {
  //.. receive frame
  }
  

• And is it the same for the || operator?

• And how can i force evaluating all values in an if-statement (even if i check 3 variables)

Here's the underlying struct for frame:

typedef struct uvc_frame {
   void *data;
   size_t data_bytes;
   uint32_t width;
   uint32_t height;
   enum uvc_frame_format frame_format;
   size_t step;
   uint32_t sequence;
   struct timeval capture_time;
   uvc_device_handle_t *source;
   uint8_t library_owns_data;
 } uvc_frame_t;

Answer 1

I'm not sure wheter this statement could throw an segmentation fault

It won't seg fault. It is in fact a typical application of short-circuit logical operators.

And is it the same for while loop conditions?

Yes.

Short circuit evaluation is not a property of if-condition or while-condition. It is the property of the expression itself. It is still short circuit even if it is not used as a condition.

For example, this is still short-circuited:

bool x = frame != NULL && frame->data != NULL;

And is it the same for the || operator?

Yup. It is also short circuit.

Well, not exactly. OR relation get it short-circuited when the first part is TRUE. That is not exactly the same as AND.