Cygwin's default person interface is the bash shell running within the mintty terminal emulator.[25] The DLL also implements pseudo terminal (pty) devices, and Cygwin ships with numerous terminal emulators which are according to them, which includes rxvt/urxvt and xterm. The Edition of GCC that comes with Cygwin has numerous extensions https://acgwin19518.blogerus.com/58958921/acgwin-for-dummies