Synopsis

Ensure that floating-point conversions are within range of the new type

Enabled by default

Yes

Severity/Certainty

Low/Low

Full description

If a floating-point value is to be converted to a floating-point value of a smaller range and precision or to an integer type, or if an integer type is to be converted to a floating-point type, the value must be representable in the destination type.

Coding standards

Code examples

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

void func(float f_a) {
  int i_a;
  /* Undefined if the integral part of f_a cannot be represented. */
  i_a = f_a;
}

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

#include <float.h>
#include <limits.h>
#include <math.h>
#include <stddef.h>
#include <stdint.h>
  
extern size_t popcount(uintmax_t); /* See INT35-C */
#define PRECISION(umax_value) popcount(umax_value)
  
void func(float f_a) {
  int i_a;
  
  if (isnan(f_a) ||
      PRECISION(INT_MAX) < log2f(fabsf(f_a)) ||
      (f_a != 0.0F && fabsf(f_a) < FLT_MIN)) {
    /* Handle error */
  } else {
    i_a = f_a;
  }
}