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=proto
int duk_pcall(duk_context *ctx, int nargs);
=stack
[ ... func! arg1! ...! argN! ] -> [ ... retval! ] (if success, return value == 0)
[ ... func! arg1! ...! argN! ] -> [ ... err! ] (if failure, return value != 0)
=summary
<p>Call target function <code>func</code> with <code>nargs</code> arguments
(not counting the function itself). The function and its arguments
are replaced by a single return value or a single error value.
An error thrown during the function call is caught.</p>
<p>The return value is:</p>
<ul>
<li><code>DUK_EXEC_SUCCESS</code> (0): call succeeded, <code>nargs</code> arguments are replaced
with a single return value. (This return code constant is guaranteed to be zero, so
that one can check for success with a "zero or non-zero" check.)</li>
<li><code>DUK_EXEC_ERROR</code>: call failed, <code>nargs</code> arguments are replaced with a
single error value. (In exceptional cases, e.g. when there are too few
arguments on the value stack, the call returns non-zero but may leave the stack
in an inconsistent state.)</li>
</ul>
<div class="note">
Unlike most Duktape API calls, this call returns zero on success. This allows
multiple error codes to be defined later.
</div>
<p>The target function <code>this</code> binding is initially set to
<code>undefined</code>. If the target function is not strict, the binding
is replaced by the global object before the function is invoked; see
<a href="http://www.ecma-international.org/ecma-262/5.1/#sec-10.4.3">Entering Function Code</a>.
If you want to control the <code>this</code> binding, you can use
<code><a href="#duk_pcall_method">duk_pcall_method()</a></code> or
<code><a href="#duk_pcall_prop">duk_pcall_prop()</a></code> instead.</p>
=example
/* Assume target function is already on stack at func_idx; the target
* function adds arguments and returns the result.
*/
int func_idx;
int rc;
duk_dup(ctx, func_idx);
duk_push_int(ctx, 2);
duk_push_int(ctx, 3);
rc = duk_pcall(ctx, 2); /* [ ... func 2 3 ] -> [ 5 ] */
if (rc == DUK_EXEC_SUCCESS) {
printf("2+3=%d\n", duk_get_int(ctx, -1));
} else {
printf("error: %s\n", duk_to_string(ctx, -1));
}
duk_pop(ctx);
=tags
call
=seealso
duk_pcall_method
duk_pcall_prop