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67 lines
2.4 KiB
67 lines
2.4 KiB
name: duk_pcall
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proto: |
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duk_int_t duk_pcall(duk_context *ctx, duk_idx_t nargs);
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stack: |
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[ ... func! arg1! ...! argN! ] -> [ ... retval! ] (if success, return value == 0)
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[ ... func! arg1! ...! argN! ] -> [ ... err! ] (if failure, return value != 0)
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summary: |
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<p>Call target function <code>func</code> with <code>nargs</code> arguments
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(not counting the function itself). The function and its arguments
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are replaced by a single return value or a single error value.
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An error thrown during the function call is caught.</p>
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<p>The return value is:</p>
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<ul>
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<li><code>DUK_EXEC_SUCCESS</code> (0): call succeeded, <code>nargs</code> arguments are replaced
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with a single return value. (This return code constant is guaranteed to be zero, so
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that one can check for success with a "zero or non-zero" check.)</li>
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<li><code>DUK_EXEC_ERROR</code>: call failed, <code>nargs</code> arguments are replaced with a
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single error value. (In exceptional cases, e.g. when there are too few
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arguments on the value stack, the call returns non-zero but may leave the stack
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in an inconsistent state.)</li>
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</ul>
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<div class="note">
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Unlike most Duktape API calls, this call returns zero on success. This allows
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multiple error codes to be defined later.
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</div>
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<p>The target function <code>this</code> binding is initially set to
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<code>undefined</code>. If the target function is not strict, the binding
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is replaced by the global object before the function is invoked; see
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<a href="http://www.ecma-international.org/ecma-262/5.1/#sec-10.4.3">Entering Function Code</a>.
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If you want to control the <code>this</code> binding, you can use
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<code><a href="#duk_pcall_method">duk_pcall_method()</a></code> or
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<code><a href="#duk_pcall_prop">duk_pcall_prop()</a></code> instead.</p>
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example: |
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/* Assume target function is already on stack at func_idx; the target
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* function adds arguments and returns the result.
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*/
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duk_idx_t func_idx;
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duk_int_t rc;
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duk_dup(ctx, func_idx);
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duk_push_int(ctx, 2);
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duk_push_int(ctx, 3);
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rc = duk_pcall(ctx, 2); /* [ ... func 2 3 ] -> [ 5 ] */
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if (rc == DUK_EXEC_SUCCESS) {
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printf("2+3=%ld\n", (long) duk_get_int(ctx, -1));
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} else {
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printf("error: %s\n", duk_to_string(ctx, -1));
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}
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duk_pop(ctx);
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tags:
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- call
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- protected
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seealso:
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- duk_pcall_method
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- duk_pcall_prop
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introduced: 1.0.0
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