Compiler Warning (level 4, off) C4365

'action' : conversion from 'type_1' to 'type_2', signed/unsigned mismatch

Remarks

For example, you tried to convert an unsigned value to a signed value. This pattern can cause unexpected results when the source value at runtime in not in the range of the destination type. Such as a negative value being converted into a signed value.

C4365 is off by default. For more information, see Compiler Warnings That Are Off by Default.

Example

The following example generates C4365.

// C4365.cpp
// compile with: /W4
#pragma warning(default:4365)

int f(int) { return 0; }
void Test(size_t i) {}

int main() {
   unsigned int n = 10;
   int o = 10;
   n++;
   f(n);   // C4365
   f(o);   // OK

   Test( -19 );   // C4365
}