duktape/website/api/duk_error.yaml

name: duk_error

proto: |
    duk_ret_t duk_error(duk_context *ctx, duk_errcode_t err_code, const char *fmt, ...);

stack: |
    [ ... ] -> [ ... err! ]

summary: |
  <p>Push a new Error object to the stack and throw it.
  This call never returns.</p>

  <p>The <code>message</code> property of the error object will be set to a <code>sprintf</code>-formatted
  string using <code>fmt</code> and the remaining arguments.  The internal prototype for the created
  error object is chosen based on <code>err_code</code>.  For instance, <code>DUK_ERR_RANGE_ERROR</code>
  causes the built-in <code>RangeError</code> prototype to be used.  The valid range for user error codes
  is [1,16777215].</p>

  <p>To push an Error object to the stack without throwing it, use
  <code><a href="#duk_push_error_object">duk_push_error_object()</a></code>.
  </p>

  <p>Even though the function never returns, the prototype describes a return
  value which allows code such as:</p>
  <pre class="c-code">
  if (argvalue &lt; 0) {
      return duk_error(ctx, DUK_ERR_TYPE_ERROR, "invalid argument value: %d", (int) argvalue);
  }
  </pre>

  <p>If the return value is ignored, cast to void to avoid compilation
  warnings:</p>
  <pre class="c-code">
  if (argvalue &lt; 0) {
      (void) duk_error(ctx, DUK_ERR_TYPE_ERROR, "invalid argument value: %d", (int) argvalue);
  }
  </pre>  

example: |
    (void) duk_error(ctx, DUK_ERR_RANGE_ERROR, "argument out of range: %d", (int) argval);

tags:
  - error

seealso:
  - duk_error_va
  - duk_throw
  - duk_push_error_object
  - duk_generic_error
  - duk_eval_error
  - duk_range_error
  - duk_reference_error
  - duk_syntax_error
  - duk_type_error
  - duk_uri_error

introduced: 1.0.0