Hello, I have constructed another demonstration program. #include <errno.h> #include <stdio.h> #include <stdlib.h> int main(void) { FILE *f = fopen("/dev/full", "a"); if (!f) goto report_failure; { int const c = 'X'; if (fputc(c, f) != c) goto report_failure; } return EXIT_SUCCESS; report_failure: perror(__func__); return errno; } I got the following result. elfring@Sonne:~/Projekte/selftests> gcc-7 putc_into_full_file1.c && ./a.out; echo $? 0 Does such a simple test example need further software development considerations? Regards, Markus -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html