[cs631apue] Openmax.c fails earlier than expected

[Jan Schaumann]

Charles Magyar IV <cmagyar at stevens.edu> wrote:

> I change the limit to unlimited, and the program starts to throw issues at file # 3249.  I had 8 files already open.
> With 8 files open, I would expect it to fail at 3396.

Ah, I see what's going on here.

Take a close look at _when_ we generate the error
message, and _what_ the error message is exactly.

>         for (int i = count; i <= num + 1; i++) {
>                 if ((fd = open("/dev/null", O_RDONLY)) < 0) {
>                         if (errno == EMFILE) {
>                                 printf("Opened %d additional files, then failed due to limit.\n", i - count);
>                                 break;

What is 'errno' here, and what is the error message
printed by strerror(errno)?

>                         } else {
>         fprintf(stdout, "File # %d err\n",i);
>         fprintf(stderr, "Unable to open '/dev/null': %s\n",
>                                                 strerror(errno));
>                         }

And what is 'errno' _here_, and what is the error
message printed by strerror(errno)?


I'm sure you can pinpoint the difference - then go one
step further and see if you can find out what the
difference in the numbers you expected and the ones
you observed are.

-Jan