#include #include #include #include #include "test_helpers.h" int main(void) { int status = isatty(STDOUT_FILENO); if (status == 1) { puts("'Tis a tty :D"); } else if (status == 0) { if (errno == ENOTTY) { // I wouldn't consider stdout not being a TTY an error // (CI runners, etc.) puts("Whatever a tty is, it's not me"); } else { perror("isatty"); exit(EXIT_FAILURE); } } else { printf("isatty returned %d, unexpected result\n", status); exit(EXIT_FAILURE); } }