Hi, my app suddenly crashed inside the QBasicAtomicInt::ref() function. I see it's because of some foolishly uninitialized pointers, so I should be able to remedy the situation shortly. So what happened and how to debug it is out of question. Rather, I'm baffled by the function itself:
Qt Code: 
  1. inline bool QBasicAtomicInt::ref()
  2. {
  3.     unsigned char ret;
  4.     asm volatile("lock\n"
  5.                  "incl %0\n"
  6.                  "setne %1"
  7.                  : "=m" (_q_value), "=qm" (ret)
  8.                  : "m" (_q_value)
  9.                  : "memory");
  10.     return ret != 0;
  11. }
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What is it supposed to do? How does it do it? How does asm keyword combine with volatile? Why are asm commands quoted? What are the colons ( : ) doing here? What could '"m" (_q_value)' possibly mean? Please, someone, explain the magic to me