The Linux kernel uses the following: kernel/futex.c:3778: SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, struct __kernel_timespec __user *, utime, u32 __user *, uaddr2, u32, val3)
Since there is no glibc wrapper, use the same types the kernel uses. Signed-off-by: Alejandro Colomar <colomar.6....@gmail.com> --- man2/futex.2 | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/man2/futex.2 b/man2/futex.2 index 837adbd25..73de71623 100644 --- a/man2/futex.2 +++ b/man2/futex.2 @@ -26,12 +26,13 @@ futex \- fast user-space locking .nf .PP .B #include <linux/futex.h> +.B #include <stdint.h> .B #include <sys/time.h> .PP -.BI "int futex(int *" uaddr ", int " futex_op ", int " val , +.BI "long futex(uint32_t *" uaddr ", int " futex_op ", uint32_t " val , .BI " const struct timespec *" timeout , \ " \fR /* or: \fBuint32_t \fIval2\fP */" -.BI " int *" uaddr2 ", int " val3 ); +.BI " uint32_t *" uaddr2 ", uint32_t " val3 ); .fi .PP .IR Note : @@ -581,8 +582,8 @@ any of the two supplied futex words: .IP .in +4n .EX -int oldval = *(int *) uaddr2; -*(int *) uaddr2 = oldval \fIop\fP \fIoparg\fP; +uint32_t oldval = *(uint32_t *) uaddr2; +*(uint32_t *) uaddr2 = oldval \fIop\fP \fIoparg\fP; futex(uaddr, FUTEX_WAKE, val, 0, 0, 0); if (oldval \fIcmp\fP \fIcmparg\fP) futex(uaddr2, FUTEX_WAKE, val2, 0, 0, 0); @@ -1765,11 +1766,11 @@ Child (18535) 4 #define errExit(msg) do { perror(msg); exit(EXIT_FAILURE); \e } while (0) -static int *futex1, *futex2, *iaddr; +static uint32_t *futex1, *futex2, *iaddr; static int -futex(int *uaddr, int futex_op, int val, - const struct timespec *timeout, int *uaddr2, int val3) +futex(uint32_t *uaddr, int futex_op, uint32_t val, + const struct timespec *timeout, uint32_t *uaddr2, uint32_t val3) { return syscall(SYS_futex, uaddr, futex_op, val, timeout, uaddr2, val3); @@ -1779,9 +1780,9 @@ futex(int *uaddr, int futex_op, int val, become 1, and then set the value to 0. */ static void -fwait(int *futexp) +fwait(uint32_t *futexp) { - int s; + long s; /* atomic_compare_exchange_strong(ptr, oldval, newval) atomically performs the equivalent of: @@ -1794,7 +1795,7 @@ fwait(int *futexp) while (1) { /* Is the futex available? */ - const int one = 1; + const uint32_t one = 1; if (atomic_compare_exchange_strong(futexp, &one, 0)) break; /* Yes */ @@ -1811,13 +1812,13 @@ fwait(int *futexp) so that if the peer is blocked in fpost(), it can proceed. */ static void -fpost(int *futexp) +fpost(uint32_t *futexp) { - int s; + long s; /* atomic_compare_exchange_strong() was described in comments above */ - const int zero = 0; + const uint32_t zero = 0; if (atomic_compare_exchange_strong(futexp, &zero, 1)) { s = futex(futexp, FUTEX_WAKE, 1, NULL, NULL, 0); if (s == \-1) -- 2.28.0