isatty(3) Library Functions Manual isatty(3) isatty - , LIBRARY Standard C library (libc, -lc) #include int isatty(int fd); isatty() , fd . isatty() 1, fd , ; 0, errno . EBADF fd . ENOTTY fd , . EINVAL ( POSIX, ENOTTY). attributes(7). +----------------------------+----------------------------------------------------------+--------------------------+ | | | | +----------------------------+----------------------------------------------------------+--------------------------+ |isatty() | | MT-Safe | +----------------------------+----------------------------------------------------------+--------------------------+ POSIX.1-2008. POSIX.1-2001, SVr4, 4.3BSD. . fstat(2), ttyname(3) Azamat Hackimov , Dmitriy S. Seregin , Yuri Kozlov ; GNU 3 , . . , , . Linux man-pages 6.06 31 2023 . isatty(3)