isatty function

C

Function

Reference manual

@see ttyname function

The isatty function checks whether the given file descriptor refers to a terminal.

Syntax

#include <unistd.h>

int isatty(int fd);

Parameters

• fd: The file descriptor to be checked.

Return value

If the given file descriptor refers to a terminal the function returns 1, otherwise it returns 0.

Usage example

In the following example we use the isatty funtion to check if standard input refers to a terminal.

#include <stdio.h>
#include <unistd.h>

int main(void) {
    int fd;

    fd = 0;
    if (isatty(fd))
        printf("File descriptor %d refers to a terminal.\n", fd);
    else
        printf("File descriptor %d does not refer to a terminal.\n", fd);
    return (0);
}