https://github.com/hslam/sem
Package sem provides a way to use System V semaphores.
https://github.com/hslam/sem
go golang ipc sem semaphore semget system-v unix
Last synced: 15 days ago
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Package sem provides a way to use System V semaphores.
- Host: GitHub
- URL: https://github.com/hslam/sem
- Owner: hslam
- License: mit
- Created: 2020-11-28T11:17:57.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2021-01-16T18:52:31.000Z (over 4 years ago)
- Last Synced: 2025-03-30T11:32:46.526Z (about 1 month ago)
- Topics: go, golang, ipc, sem, semaphore, semget, system-v, unix
- Language: Go
- Homepage:
- Size: 15.6 KB
- Stars: 6
- Watchers: 1
- Forks: 5
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# sem
[](https://pkg.go.dev/github.com/hslam/sem)
[](https://github.com/hslam/sem/actions)
[](https://goreportcard.com/report/github.com/hslam/sem)
[](https://github.com/hslam/sem/blob/master/LICENSE)
Package sem provides a way to use System V semaphores.
## Get started
### Install
```
go get github.com/hslam/sem
```
### Import
```
import "github.com/hslam/sem"
```
### Usage
#### Example
```go
package main
import (
"fmt"
"github.com/hslam/ftok"
"github.com/hslam/sem"
"time"
)
func main() {
key, err := ftok.Ftok("/tmp", 0x22)
if err != nil {
panic(err)
}
nsems := 1
semid, err := sem.Get(key, nsems, 0666)
if err != nil {
semid, err = sem.Get(key, nsems, sem.IPC_CREAT|sem.IPC_EXCL|0666)
if err != nil {
panic(err)
}
defer sem.Remove(semid)
for semnum := 0; semnum < nsems; semnum++ {
_, err := sem.SetValue(semid, semnum, 1)
if err != nil {
panic(err)
}
}
}
semnum := 0
if count, err := sem.GetValue(semid, semnum); err != nil {
panic(err)
} else if count == 0 {
fmt.Printf("%s semnum %d wait\n", time.Now().Format("15:04:05"), semnum)
}
ok, err := sem.P(semid, semnum, sem.SEM_UNDO)
if err != nil {
panic(err)
}
fmt.Printf("%s semnum %d P %t\n", time.Now().Format("15:04:05"), semnum, ok)
time.Sleep(time.Second * 10)
ok, err = sem.V(semid, semnum, sem.SEM_UNDO)
if err != nil {
panic(err)
}
fmt.Printf("%s semnum %d V %t\n", time.Now().Format("15:04:05"), semnum, ok)
time.Sleep(time.Second * 20)
}
```
#### Output
```sh
$ go run main.go
12:35:21 semnum 0 P true
12:35:31 semnum 0 V true
```
In another terminal.
```sh
$ go run main.go
12:35:25 semnum 0 wait
12:35:31 semnum 0 P true
12:35:41 semnum 0 V true
```
### License
This package is licensed under a MIT license (Copyright (c) 2020 Meng Huang)
### Author
sem was written by Meng Huang.