Menu
Search

API Documentation

version 2.111.0

overview

View source code
Display the source code in core/checkedint.d from which thispage was generated on github.
Report a bug
If you spot a problem with this page, click here to create aBugzilla issue.
Improve this page
Quickly fork, edit online, and submit a pull request for this page.Requires a signed-in GitHub account. This works well for small changes.If you'd like to make larger changes you may want to consider usinglocal clone.

Function core.checkedint.muls

Multiply two signed integers, checking for overflow.

int muls(
  int x,
  int y,
  ref bool overflow
);

long muls(
  long x,
  long y,
  ref bool overflow
);

The overflow is sticky, meaning a sequence of operations can be done and overflow need only be checked at the end.

Parameters

NameDescription
x left operand
y right operand
overflow set if an overflow occurs, is not affected otherwise

Returns

the product

Example

bool overflow;
writeln(muls(2, 3, overflow)); // 6
assert(!overflow);

writeln(muls(-200, 300, overflow)); // -60_000
assert(!overflow);

writeln(muls(1, int.max, overflow)); // int.max
assert(!overflow);

writeln(muls(int.min, 1, overflow)); // int.min
assert(!overflow);

writeln(muls(int.max, 2, overflow)); // (int.max * 2)
assert(overflow);

overflow = false;
writeln(muls(int.min, -1, overflow)); // int.min
assert(overflow);

writeln(muls(0, 0, overflow)); // 0
assert(overflow);                   // sticky

Example

bool overflow;
writeln(muls(2L, 3L, overflow)); // 6
assert(!overflow);

writeln(muls(-200L, 300L, overflow)); // -60_000
assert(!overflow);

writeln(muls(1, long.max, overflow)); // long.max
assert(!overflow);

writeln(muls(long.min, 1L, overflow)); // long.min
assert(!overflow);

writeln(muls(long.max, 2L, overflow)); // (long.max * 2)
assert(overflow);
overflow = false;

writeln(muls(-1L, long.min, overflow)); // long.min
assert(overflow);

overflow = false;
writeln(muls(long.min, -1L, overflow)); // long.min
assert(overflow);

writeln(muls(0L, 0L, overflow)); // 0
assert(overflow);                   // sticky

Authors

Walter Bright

License

Boost License 1.0