1 files changed, 13 insertions, 0 deletions
diff --git a/src/unistd/isatty.c b/src/unistd/isatty.c
new file mode 100644
index 0000000..75a9c18
--- /dev/null
+++ b/src/unistd/isatty.c
@@ -0,0 +1,13 @@
+#include <unistd.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include "syscall.h"
+
+int isatty(int fd)
+{
+	struct winsize wsz;
+	unsigned long r = syscall(SYS_ioctl, fd, TIOCGWINSZ, &wsz);
+	if (r == 0) return 1;
+	if (errno != EBADF) errno = ENOTTY;
+	return 0;
+}