In tcsetattr(), first initialize the mode structure by calling

gvanrossum · gvanrossum · commit e7c419375584 · 1998-06-12T14:26:18.000Z
tcgetattr().  This seems to be the only correct way to cope with
platform-specific structure members...
diff --git a/Modules/termios.c b/Modules/termios.c
@@ -139,6 +139,9 @@ termios_tcsetattr(self, args)
 		return NULL;
 	}
 
+	/* Get the old mode, in case there are any hidden fields... */
+	if (tcgetattr(fd, &mode) == -1)
+		return PyErr_SetFromErrno(TermiosError);
 	mode.c_iflag = (tcflag_t) PyInt_AsLong(PyList_GetItem(term, 0));
 	mode.c_oflag = (tcflag_t) PyInt_AsLong(PyList_GetItem(term, 1));
 	mode.c_cflag = (tcflag_t) PyInt_AsLong(PyList_GetItem(term, 2));

Original file line number	Diff line number	Diff line change
`@@ -139,6 +139,9 @@ termios_tcsetattr(self, args)`
`139`	`139`	`return NULL;`
`140`	`140`	`}`
`141`	`141`
	`142`	`+ /* Get the old mode, in case there are any hidden fields... */`
	`143`	`+ if (tcgetattr(fd, &mode) == -1)`
	`144`	`+ return PyErr_SetFromErrno(TermiosError);`
`142`	`145`	`mode.c_iflag = (tcflag_t) PyInt_AsLong(PyList_GetItem(term, 0));`
`143`	`146`	`mode.c_oflag = (tcflag_t) PyInt_AsLong(PyList_GetItem(term, 1));`
`144`	`147`	`mode.c_cflag = (tcflag_t) PyInt_AsLong(PyList_GetItem(term, 2));`