ISATTY(3C)ISATTY(3C)NAMEisatty - test for a terminal device
SYNOPSIS
#include <unistd.h>
int isatty(int fildes);
DESCRIPTION
The isatty() function tests whether fildes, an open file descriptor, is
associated with a terminal device.
RETURN VALUES
The isatty() function returns 1 if fildes is associated with a termi‐
nal; otherwise it returns 0 and may set errno to indicate the error.
ERRORS
The isatty() function may fail if:
EBADF
The fildes argument is not a valid open file descriptor.
ENOTTY
The fildes argument is not associated with a terminal.
USAGE
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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOttyname(3C), attributes(5), standards(5)
Jul 24, 2002 ISATTY(3C)