ISATTY(3C) Standard C Library Functions ISATTY(3C)

isatty - test for a terminal device

#include <unistd.h>
int isatty(int fildes);

The isatty() function tests whether fildes, an open file descriptor, is associated with a terminal device.

The isatty() function returns 1 if fildes is associated with a terminal; otherwise it returns 0 and may set errno to indicate the error.

The isatty() function may fail if:


The fildes argument is not a valid open file descriptor.


The fildes argument is not associated with a terminal.

The isatty() function does not necessarily indicate that a human being is available for interaction via fildes. It is quite possible that non-terminal devices are connected to the communications line.

See attributes(7) for descriptions of the following attributes:

Interface Stability Standard
MT-Level MT-Safe

ttyname(3C), attributes(7), standards(7)

July 24, 2002 OmniOS