1 files changed, 29 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/isatty.c b/sysdeps/unix/sysv/linux/isatty.c
new file mode 100644
index 0000000..3faaec5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/isatty.c
@@ -0,0 +1,29 @@
+/* Test whether a file descriptor refers to a terminal.  Linux version.
+   Copyright (C) 1991-2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <termios_internals.h>
+
+/* Return 1 if FD is a terminal, 0 if not. This simply does a
+   TCGETS2 ioctl into a dummy buffer without parsing the result. */
+int
+__isatty (int fd)
+{
+  struct termios2 k_termios;
+  return INLINE_SYSCALL_CALL (ioctl, fd, TCGETS2, &k_termios) == 0;
+}
+weak_alias (__isatty, isatty)