i had to think a bit about what rw_lock returns, so i made this. is this worth it?
Index: rwlock.9 =================================================================== RCS file: /cvs/src/share/man/man9/rwlock.9,v retrieving revision 1.23 diff -u -p -r1.23 rwlock.9 --- rwlock.9 4 Jun 2018 04:52:33 -0000 1.23 +++ rwlock.9 25 Feb 2019 01:27:21 -0000 @@ -188,19 +188,7 @@ functions check the status panicking if it is not write-, read-, any-, or unlocked, respectively. .Pp .Nm rw_status -returns the current state of the lock: -.Pp -.Bl -tag -width "RW_WRITE_OTHER" -offset indent -compact -.It Dv RW_WRITE -Lock is write locked by the calling thread. -.It Dv RW_WRITE_OTHER -Lock is write locked by a different thread. -.It Dv RW_READ -Lock is read locked. -The current thread may be one of the threads that has it locked. -.It 0 -Lock is not locked. -.El +returns the current state of the lock. .Pp A lock declaration may be initialised with the .Fn RWLOCK_INITIALIZER @@ -223,6 +211,30 @@ and can be called during autoconf, from process context, or from interrupt context. .Pp All other functions can be called during autoconf or from process context. +.Sh RETURN VALUES +.Nm rw_enter +and +.Nm rrw_enter +return 0 on success, or an +.Xr errno 2 +style value on failure. +.Pp +.Nm rw_status +and +.Nm rrw_status +return the state of the lock: +.Pp +.Bl -tag -width "RW_WRITE_OTHER" -offset indent -compact +.It Dv RW_WRITE +Lock is write locked by the calling thread. +.It Dv RW_WRITE_OTHER +Lock is write locked by a different thread. +.It Dv RW_READ +Lock is read locked. +The current thread may be one of the threads that has it locked. +.It 0 +Lock is not locked. +.El .Sh SEE ALSO .Xr witness 4 , .Xr mutex 9 ,
