- Pseudo console support introduced by commit 169d65a5774acc76ce3f3feeedcbae7405aa9b57 shows garbage ^[[H^[[J in some of emacs screens. These screens do not handle ANSI escape sequences. Therefore, clear screen is disabled on these screens. --- winsup/cygwin/fhandler_tty.cc | 26 +++++++++++++++++++------- winsup/cygwin/tty.cc | 1 + winsup/cygwin/tty.h | 1 + 3 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc index 283558985..a74c3eecf 100644 --- a/winsup/cygwin/fhandler_tty.cc +++ b/winsup/cygwin/fhandler_tty.cc @@ -972,6 +972,19 @@ skip_console_setting: void fhandler_pty_slave::reset_switch_to_pcon (void) { + if (get_ttyp ()->need_clear_screen) + { + const char *term = getenv ("TERM"); + if (term && strcmp (term, "dumb") && !strstr (term, "emacs")) + { + /* FIXME: Clearing sequence may not be "^[[H^[[J" + depending on the terminal type. */ + DWORD n; + WriteFile (get_output_handle_cyg (), "\033[H\033[J", 6, &n, NULL); + } + get_ttyp ()->need_clear_screen = false; + } + if (ALWAYS_USE_PCON) return; if (isHybrid) @@ -2808,14 +2821,13 @@ fhandler_pty_slave::fixup_after_attach (bool native_maybe) /* Clear screen to synchronize pseudo console screen buffer with real terminal. This is necessary because pseudo console screen buffer is empty at start. */ - /* FIXME: Clearing sequence may not be "^[[H^[[J" - depending on the terminal type. */ - DWORD n; - if (get_ttyp ()->num_pcon_attached_slaves == 0 - && !ALWAYS_USE_PCON) + const char *term = getenv ("TERM"); + if (get_ttyp ()->num_pcon_attached_slaves == 0 && + term && strcmp (term, "dumb") && + term && !strstr (term, "emacs") && + !ALWAYS_USE_PCON) /* Assume this is the first process using this pty slave. */ - WriteFile (get_output_handle_cyg (), - "\033[H\033[J", 6, &n, NULL); + get_ttyp ()->need_clear_screen = true; get_ttyp ()->num_pcon_attached_slaves ++; } diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc index 9244267c0..c94aee3ba 100644 --- a/winsup/cygwin/tty.cc +++ b/winsup/cygwin/tty.cc @@ -243,6 +243,7 @@ tty::init () pcon_pid = 0; num_pcon_attached_slaves = 0; TermCodePage = 20127; /* ASCII */ + need_clear_screen = false; } HANDLE diff --git a/winsup/cygwin/tty.h b/winsup/cygwin/tty.h index d59b2027d..c2b0490d0 100644 --- a/winsup/cygwin/tty.h +++ b/winsup/cygwin/tty.h @@ -104,6 +104,7 @@ private: pid_t pcon_pid; int num_pcon_attached_slaves; UINT TermCodePage; + bool need_clear_screen; public: HANDLE from_master () const { return _from_master; } -- 2.21.0