http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57937
Bug ID: 57937 Summary: fgets and cout tricky bug Product: gcc Version: 4.7.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: linkerpro at mail dot ru Created attachment 30529 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30529&action=edit code demostrating the bug Hi It's seem I have found very tricky bug while trying to resolve MAC addr by IP in my local network. Requerement: to use see the bug - at line 50 of attachment you should put a real host in your local network, and this host must be present in arp table. In my case 192.168.1.1 is my gateway. compiles OK without any warning $ g++ bug.cpp --std=c++0x -Wall -Wextra run (no output) $ ./a.out $ Next uncomment line 36 of attachment (simple debug cout) ! recompile OK $ g++ bug.cpp --std=c++0x -Wall -Wextra run OK $ ./a.out > 192.168.1.1 00:01:02:03:04:05 So if I put any cout in for loop - everything is OK. Ubuntu 12.10 with latest updates. $ uname -a Linux notebook 3.5.0-36-generic #57-Ubuntu SMP Wed Jun 19 15:10:49 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux