isatty - test whether a file descriptor refers to a terminal
#include <unistd.h>
int isatty(int fd);
The isatty() function tests whether fd
is an open file descriptor referring to a terminal.
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.
fd
is not a valid file descriptor.
fd
refers to a file other than a terminal. POSIX.1 specifies the error ENOTTY for this case.
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
isatty() | Thread safety | MT-Safe |
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.
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