...
This noncompliant code example leads to undefined behavior if the integral part of f1 cannot be represented as an integer.
| Code Block | ||||
|---|---|---|---|---|
| ||||
float f1; int i1; /* initialize fl */ i1 = f1; /* Undefined if the integral part of f1 > INT_MAX */ |
...
This compliant solution assumes that the range of floating-point values is greater than that of an int. (This is the case in almost all implementations.) Unfortunately, there is no safe way to inquire about this assumption in the code short of already knowing the implementation.
| Code Block | ||||
|---|---|---|---|---|
| ||||
float f1;
int i1;
/* initialize fl */
if (f1 > (float) INT_MAX || f1 < (float) INT_MIN) {
/* Handle error */
} else {
i1 = f1;
}
|
...
This noncompliant code example contains conversions that may be outside of the range of the demoted types.
| Code Block | ||||
|---|---|---|---|---|
| ||||
long double ld; double d1; double d2; float f1; float f2; /* initializations */ f1 = (float)d1; f2 = (float)ld; d2 = (double)ld; |
...
This compliant solution checks to see whether the values to be stored can be represented in the new type.
| Code Block | ||||
|---|---|---|---|---|
| ||||
#include <float.h>
long double ld;
double d1;
double d2;
float f1;
float f2;
/* initializations */
if (d1 > FLT_MAX || d1 < -FLT_MAX) {
/* Handle error condition */
} else {
f1 = (float)d1;
}
if (ld > FLT_MAX || ld < -FLT_MAX) {
/* Handle error condition */
} else {
f2 = (float)ld;
}
if (ld > DBL_MAX || ld < -DBL_MAX) {
/* Handle error condition */
} else {
d2 = (double)ld;
}
|
...