I have a GTK program running on Ubuntu 10.04 that hangs in interruptible state, and I'd like to understand the output of `strace`. In particular, I have this line:

```
read(5, 0x2ba9ac4, 4096) = -1 EAGAIN (Resource temporarily unavailable)

```

I suspect `5` is the file descriptor, `0x2ba9ac4` the address in this file to be read, and `4096` the amount of data to read. Can you confirm? More importantly, how can one determine which file the program is trying to read? This file descriptor does not exist in `/proc/pid/fd` (which is probably why the program hangs).