The futex.2 system call makes no assumption about the meaning of the values of a futex. It may check if the value changes. The current futex.7 speaks of incrementing and decrementing a futex. That choice is arbitrary and unwise as overflows may occur. If special considerations for the usage of futex.2 have to be made in a futex.7 example, this should be explained in futex.7 Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx> --- man2/futex.2 | 33 +-------------------------------- 1 file changed, 1 insertion(+), 32 deletions(-) diff --git a/man2/futex.2 b/man2/futex.2 index 6c02da7..0ea7db2 100644 --- a/man2/futex.2 +++ b/man2/futex.2 @@ -68,16 +68,6 @@ When a futex operation did not finish uncontended in user space, a call needs to be made to the kernel to arbitrate. Arbitration can either mean putting the caller to sleep or, conversely, waking a waiting process or thread. -.PP -Callers of -.BR futex () -are expected to adhere to the semantics described in -.BR futex (7). -As these semantics involve writing nonportable assembly instructions -(see the example library referred to in SEE ALSO), -this in turn probably means that most users will in fact be -library authors and not general application developers. -.\" .SS Arguments The .I uaddr @@ -229,18 +219,6 @@ The arguments and .I val3 are ignored. - -For -.BR futex (7), -this call is executed if decrementing the count gave a negative value -(indicating contention), -and will sleep until another process or thread releases -the futex and executes the -.B FUTEX_WAKE -operation. -.\" -.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" -.\" .TP .BR FUTEX_WAKE " (since Linux 2.6.0)" .\" Strictly speaking, since Linux 2.5.x @@ -266,15 +244,6 @@ The arguments and .I val3 are ignored. - -For -.BR futex (7), -this is executed if incrementing the count showed that there were waiters, -.\" FIXME How does "incrementing the count showed that there were waiters"? -once the futex value has been set to 1 (indicating that it is available). -.\" -.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" -.\" .TP .BR FUTEX_FD " (from Linux 2.6.0 up to and including Linux 2.6.25)" .\" Strictly speaking, from Linux 2.5.x to 2.6.25 @@ -304,7 +273,7 @@ and are ignored. To prevent race conditions, the caller should test if the futex has -been upped after +been changed after .B FUTEX_FD returns. -- 2.1.4 -- 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
