GCC -lm -lz -lrt options - what are they about?

Question

I know, that these are some common/basic libraries, but what do they mean exactly?

For example, I know, that -lm is some math library, but is this the st

Answer 1

libm http://refspecs.freestandards.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/libm.html

libz http://refspecs.freestandards.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/libzman.html

librt http://www.rdg.ac.uk:8081/cgi-bin/cgiwrap/wsi14/poplog/man/3LIB/librt

All of them are standard C afaik, probably included in libstdc++ (your question is tagged C++).