Simplify isatty()

sources/fileno.c

@@ -1,14 +1,11 @@
 #include <stdio.h>
+#include <errno.h>
 #include "lib.h"
 
-int fileno(FILE *stream)
+int (fileno)(FILE *stream)
 {
     if (stream != NULL)
         return FILE_GET_HANDLE(stream);
-    else
-    {
-        // errno = EBADF;
-        return -1;
-    }
-
-}
+    __set_errno(EBADF);
+    return -1;
+}

sources/isatty.c

@@ -1,39 +1,11 @@
 #include <mint/mintbind.h>
-#include <mint/errno.h>
 #include <unistd.h>
 
-#ifndef TIOCGPGRP
-#define TIOCGPGRP (('T'<< 8) | 6)
-#endif
+int isatty (int handle) {
+	long r, pos;
 
-int isatty (int fd) {
-	long dummy, retval;
-	int rc;
-
-	retval = Fcntl (fd, &dummy, TIOCGPGRP);
-	if (retval == -ENOSYS) {
-		long oldloc;
-
-		/* save current location */
-		oldloc = Fseek (0L, fd, SEEK_CUR);
-
-		/* try to seek ahead one byte */
-		if (Fseek (1L, fd, SEEK_CUR) != 0) {
-			/* got either a file position or an error (usually
-			 * EBADARG indicating a range error from trying to
-			 * seek past EOF), so it is not a tty
-			 */
-			rc = 0;
-
-			/* seek back to original location */
-			(void) Fseek (oldloc, fd, SEEK_SET);
-		}
-		else  {
-			rc = 1; /* yes, tty */
-		}
-	}
-	else {
-		rc = (retval == 0);
-	}
-	return rc;
+	pos = Fseek(0, handle, SEEK_CUR);
+	r = Fseek(1, handle, SEEK_SET);
+	Fseek(pos, handle, SEEK_SET);
+	return r == 0;
 }