/tmp/cc5z872x.o: In function `threadedmult(Matrix::matrix*, Matrix::matrix*, Matrix::matrix*)':
foo.cc:(.text+0x17e): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。