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Name

isatty - test whether a file descriptor refers to a terminal

Synopsis


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

Description

The isatty() function tests whether fd is an open file descriptor referring to a terminal.

Return Value

isatty() returns 1 if fd is an open file descriptor referring to a terminal; otherwise 0 is returned, and errno is set to indicate the error.

Errors

EBADF
fd is not a valid file descriptor.
EINVAL
fd refers to a file other than a terminal. POSIX.1-2001 specifies the error ENOTTY for this case.

Attributes

Multithreading (see pthreads(7) )

The isatty() function is thread-safe.

Conforming to

SVr4, 4.3BSD, POSIX.1-2001.

See Also

fstat(2) , ttyname(3)

Colophon

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