From 0142fd8f369e2950386ff3478024c2d21781181a Mon Sep 17 00:00:00 2001
From: hslam <791874158@qq.com>
Date: Tue, 1 Dec 2020 19:03:18 +0800
Subject: [PATCH] update sem methods

---
 ipc_test.go |  9 ++++-----
 sem.go      | 42 ++++++++++++++++++++++++++++++++++++------
 2 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/ipc_test.go b/ipc_test.go
index 9d342c1..561d37e 100644
--- a/ipc_test.go
+++ b/ipc_test.go
@@ -4,7 +4,6 @@
 package ipc
 
 import (
-	"github.com/hslam/sem"
 	"strings"
 	"testing"
 	"time"
@@ -182,15 +181,15 @@ func TestMore(t *testing.T) {
 	} else if ret < 1 {
 		t.Error()
 	}
-	var sops [1]sem.Sembuf
-	sops[0] = sem.Sembuf{SemNum: uint16(semnum), SemFlg: SEM_UNDO}
+	var sops [1]Sembuf
+	sops[0] = Sembuf{SemNum: uint16(semnum), SemFlg: SEM_UNDO}
 	sops[0].SemOp = -1
-	if _, err := Semop(semid, sops[:]); err != nil {
+	if _, err := Semoperate(semid, sops[:]); err != nil {
 		return
 	}
 	text := string(data[:length])
 	sops[0].SemOp = 1
-	if _, err := Semop(semid, sops[:]); err != nil {
+	if _, err := Semoperate(semid, sops[:]); err != nil {
 		return
 	}
 
diff --git a/sem.go b/sem.go
index 2cc38df..53cbf76 100644
--- a/sem.go
+++ b/sem.go
@@ -5,8 +5,16 @@ package ipc
 
 import (
 	"github.com/hslam/sem"
+	"unsafe"
 )
 
+// Sembuf represents an operation.
+type Sembuf struct {
+	SemNum uint16
+	SemOp  int16
+	SemFlg int16
+}
+
 // Semget calls the semget system call.
 //
 // The semget() system call returns the System V semaphore set identifier
@@ -56,15 +64,37 @@ func Semv(semid int, semnum int, semflg int) (bool, error) {
 }
 
 // Semop calls the semop system call.
+//
+// semop() performs operations on selected semaphores in the set indi‐
+// cated by semid.  Each of the nsops elements in the array pointed to
+// by sops is a structure that specifies an operation to be performed on
+// a single semaphore.  The elements of this structure are of type
+// struct sembuf, containing the following members:
+//
+// unsigned short sem_num;  /* semaphore number */
+// short          sem_op;   /* semaphore operation */
+// short          sem_flg;  /* operation flags */
+//
+// Flags recognized in sem_flg are IPC_NOWAIT and SEM_UNDO.
+// If an operation specifies SEM_UNDO, it will be automatically undone when the
+// process terminates.
+//
+// The set of operations contained in sops is performed in array order,
+// and atomically, that is, the operations are performed either as a
+// complete unit, or not at all.  The behavior of the system call if not
+// all operations can be performed immediately depends on the presence
+// of the IPC_NOWAIT flag in the individual sem_flg fields, as noted be‐
+// low.
+func Semop(semid int, sops uintptr, nsops int) (bool, error) {
+	return sem.Op(semid, sops, nsops)
+}
+
+// Semoperate calls the semop system call.
 // Flags recognized in SemFlg are IPC_NOWAIT and SEM_UNDO.
 // If an operation specifies SEM_UNDO, it will be automatically undone when the
 // process terminates.
-// Op calls the semop system call.
-// Flags recognized in SemFlg are IPC_NOWAIT and SEM_UNDO.
-// If an operation specifies SEM_UNDO, it will be automatically undone when the
-// process terminates.
-func Semop(semid int, sops []sem.Sembuf) (bool, error) {
-	return sem.Op(semid, sops)
+func Semoperate(semid int, sops []Sembuf) (bool, error) {
+	return Semop(semid, uintptr(unsafe.Pointer(&sops[0])), len(sops))
 }
 
 // Semrm removes the semaphore with the given id.