Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates that I went to Sayyidah Hafsah bint Umar (may Allah be pleased with them both), so I climbed onto the roof of her house. I saw the Prophet (peace and blessings of Allah be upon him) with his back towards the Qiblah and his face towards Shaam, relieving himself. These are the words of Abdul A’la’s hadith, and in Abu Hisham’s narration (hadith) « مستقبل القبلة » the words are “facing the Qiblah.”
Related hadith on this topic