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<?php $pathA = '/tmp/a.txt'; $pathB = '/tmp/b.txt'; file_put_contents($pathA, 'X'); file_put_contents($pathB, 'X'); $handleA = fopen($pathA, 'a+'); $handleB = fopen($pathB, 'a+'); assert(fwrite($handleA, 'Y') === fwrite($handleB, 'Y')); fseek($handleA, ftell($handleA)); // THIS LINE SHOULD DO NOTHING BUT CHANGES THE BEHAVIOR assert(ftell($handleA) === ftell($handleB)); $contentA = fread($handleA, 100); $contentB = fread($handleB, 100); var_dump($contentA); var_dump($contentB); assert($contentA === $contentB);

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