Description:
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The documentation says that the second argument to imagexbm (like the other functions) is optional, and that if not included, the output will be sent to stdout instead of to a file. However, on running the test script, I get a PHP Warning about the second argument missing and nothing is outputted to stdout. Changing the used function to imagegif (or any other variant) works as expected.

Test script:
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<?php

// Create a blank image and add some text
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5,  'A Simple Text String', $text_color);

// Output the image
imagexbm($im);

// Free up memory
imagedestroy($im);


Expected result:
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Output the imagexbm binary to stdout

Actual result:
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PHP Warning:  imagexbm() expects at least 2 parameters, 1 given in /tmp/test.php on line 9