int isatty(int fd);
DESCRIPTIONThe isatty() function tests whether fd is an open file descriptor referring to a terminal.
RETURN VALUEisatty() 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.
ATTRIBUTESFor an explanation of the terms used in this section, see attributes(7).
CONFORMING TOPOSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.
COLOPHONThis page is part of release 4.06 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.