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 can be depending on them, which includes rxvt/urxvt and xterm. The Edition of GCC that includes Cygwin has different extensions https://fernandooopon.blogvivi.com/37810359/detailed-notes-on-acgwin