On Mon, Jan 31, 2022 at 09:44:38PM +0100, Alejandro Colomar (man-pages) wrote: > Hello Alexander, > > On 1/31/22 19:32, Mathnerd314 wrote: > > Hi, > > > > The POSIX standard says fsync(2) can return EINTR: > > https://pubs.opengroup.org/onlinepubs/9699919799/ > > > > The man page does not: > > https://man7.org/linux/man-pages/man2/fsync.2.html > > > > I think fsync can be interrupted by a signal on Linux, so this should > > just be an oversight in the man page. > > > > At least, fsync on fuse seems be able to return EINTR: > > https://github.com/torvalds/linux/blob/5367cf1c3ad02f7f14d79733814302a96cc97b96/fs/fuse/dev.c#L114 > > > > Actually there seem to be numerous error codes that can be returned > > from all filesystem calls on fuse: ENOTCONN, ENOMEM, etc. But EINTR is > > at least documented in the POSIX standard, whereas these others seem > > really rare. But for full correctness I suppose these should be > > documented as well. It would be quite an undertaking. It's probably worth reading this part of POSIX: : 2.3 Error Numbers : : Most functions can provide an error number. The means by which each : function provides its error numbers is specified in its description. : : Some functions provide the error number in a variable accessed through : the symbol errno, defined by including the <errno.h> header. The value : of errno should only be examined when it is indicated to be valid by : a function's return value. No function in this volume of POSIX.1-2017 : shall set errno to zero. For each thread of a process, the value of : errno shall not be affected by function calls or assignments to errno : by other threads. : : Some functions return an error number directly as the function : value. These functions return a value of zero to indicate success. : : If more than one error occurs in processing a function call, any one : of the possible errors may be returned, as the order of detection is : undefined. : : Implementations may support additional errors not included in this list, : may generate errors included in this list under circumstances other : than those described here, or may contain extensions or limitations that : prevent some errors from occurring. : : The ERRORS section on each reference page specifies which error conditions : shall be detected by all implementations (``shall fail") and which may : be optionally detected by an implementation (``may fail"). If no error : condition is detected, the action requested shall be successful. If an : error condition is detected, the action requested may have been partially : performed, unless otherwise stated. So while it's worth adding EINTR to the man page, I don't think it's worth going through an exercise of trying to add every possible errno to every syscall.
