name: duk_to_boolean

proto: |
  duk_bool_t duk_to_boolean(duk_context *ctx, duk_idx_t index);

stack: |
  [ ... val! ... ] -> [ ... ToBoolean(val)! ... ]

summary: |
  <p>Replace the value at <code>index</code> with an Ecmascript
  <a href="http://www.ecma-international.org/ecma-262/5.1/#sec-9.2">ToBoolean()</a>
  coerced value.  Returns 1 if the result of the coercion <code>true</code>, 0 otherwise.
  If <code>index</code> is invalid, throws an error.</p>

  <div include="ref-custom-type-coercion.html" />

example: |
  if (duk_to_boolean(ctx, -3)) {
      printf("coerced value is true\n");
  }

tags:
  - stack

introduced: 1.0.0