GCC 4.9 does indeed support the C++11 <regex> functionality but not the tr1 version. Note that the difference is that parts (all?) of the latter exist within a tr1:: namespace while the C++11 <regex> is within namespace std. There's not much point to going backwards and adding in tr1 support when C++11 has been published for some time now.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
