In qt-x11-opensource-src-4.2.2/src/corelib/tools/qdatetime.h, line 40 has
Qt Code: 
  1. bool isNull() const { return jd == 0; }
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and line 101 has
Qt Code: 
  1. inline int toJulianDay() const { return jd; }
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As I understand it, all functions defined inside a class definition are automatically inline. Then why does line 101 have the inline keyword while line 40 does not? Is there any special meaning?