https://bugzilla.kernel.org/show_bug.cgi?id=40852 Summary: select(2): document action of close()'ing a fd during a select() Product: Documentation Version: unspecified Kernel Version: n/a Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: man-pages AssignedTo: documentation_man-pages@xxxxxxxxxxxxxxxxxxxx ReportedBy: fillods@xxxxxxxxxxxx Regression: No I had a hard time figuring out what is the Linux's expected behavior of select() syscall when a file descriptor is close()'d in the meantime. The man page 3.27-1ubuntu2 lacks this piece of information. This is on Ubuntu 11.04. Like many other OS, I would have expect select() to bail out on Linux, but it is not the case. When some other thread close() a file descriptor currently watched by select(), Linux does not make the select() syscall to return with errno=EBADF, it simply ignores it and does not return. Please note that this behavior is undefined in POSIX. IMO, this has to be appropriately documented in the select(2) man page. Maybe something like "The select() system call never returns if a file descriptor is closed in the meantime. This behavior is undefined in POSIX".[3] Rem: this case is not to be confused with a file that has already been closed before calling select(). Background: [1] http://stackoverflow.com/questions/543541/what-does-select2-do-if-you-close2-a-file-descriptor-in-a-separate-thread/543595#543595 [2] http://lkml.indiana.edu/hypermail/linux/kernel/0106.0/0768.html [3] https://lists.linux-foundation.org/pipermail/bugme-new/2003-April/008335.html -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
