Name
isatty - test whether a file descriptor refers to a terminalLibrary
Standard C library ( libc ", " -lc )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.
ENOTTY fd refers to a file other than a terminal. On some older kernels, some types of files resulted in the error EINVAL in this case (which is a violation of POSIX, which specifies the error ENOTTY ).
Attributes
For an explanation of the terms used in this section, see attributes(7).| Interface | Attribute | Value |
| T} | Thread safety | MT-Safe |