Corinna Vinschen wrote: > On May 9 05:02, IWAMURO Motonori wrote: >> When the last readdir returns NULL, python detects the error because >> readdir keeps previous errno. >> >> 1) ep = readdir(dirp); // ep->d_name == ".", errno == 0 >> Python check only ep != NULL. -> OK >> 2) ep = readdir(dirp); // ep->d_name == "..", errno == 0 >> Python check only ep != NULL. -> OK >> 3) ep = readdir(dirp); // ep->d_name == "\xe3\x82...", errno == 138 >> Python check only ep != NULL. -> OK >> 4) ep = readdir(dirp); // ep->d_name == "\xe3\x83...", errno == 138 >> Python check only ep != NULL. -> OK >> 5) ep = readdir(dirp); // ep == NULL, errno == 138 >> Python check ep == NULL and errno != 0. -> Fail! > > Ouch, right. It shows that I'm tired.
It shows that python is buggy then. It should be resetting errno itself before calling readdir, so that it can distinguish between the EOF and error conditions. http://www.opengroup.org/onlinepubs/009695399/functions/readdir.html " Upon successful completion, readdir() shall return a pointer to an object of type struct dirent. When an error is encountered, a null pointer shall be returned and errno shall be set to indicate the error. When the end of the directory is encountered, a null pointer shall be returned and errno is not changed. " ... note particularly the "not changed". Or perhaps python should test feof/ferror before deciding whether to inspect errno, but either way it shouldn't just assume that because readdir returns NULL that implies errno is valid. cheers, DaveK -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
