Process control and signal handling in Go language

Go language is an open source programming language. It is increasingly popular among programmers because of its simplicity, ease of use, efficiency and security. In the Go language, process control and signal processing are also very important parts. This article will delve into the process control and signal processing in the Go language.

Process call in Go language

Process control in Go language can realize calling and control between multiple processes. The Go language provides the os library and the exec library, which can start and call processes. By calling the command line in the os library, you can create a new process and bind its output to the standard output stream of the current process. You can also import the standard input stream of the current process into the newly created process.

In the Go language, the os.StartProcess() function is mainly used to create a new process. The prototype of this function is as follows:

func StartProcess(name string, args []string, attr os.ProcAttr) (os.Process, error)

where, name The parameter represents the executable file path of the new process; the args parameter is the command line parameter to be passed to the new process; the attr parameter can be used to specify the attributes of the new process, such as environment variables and working directory.

The sample code to start the process is as follows:

package main

import (
    "fmt"
    "os"
)

func main() {
    cmd := exec.Command("ls", "-l")
    output, err := cmd.Output()
    if err != nil {
        panic(err)
    }
    fmt.Println(string(output))
}

In this example, we start the ls command by calling the Command() function and bind its output to the standard output of the current process stream, and finally by calling the Output() function to read the output results and print them to the screen.

Signal processing

Signal is an inter-process communication mechanism, which allows the operating system to send a specific signal to the process, and the process can perform corresponding processing based on this signal. In the Go language, you can use the Signal and Signal.Notify functions of the os library to register and handle signals.

The Signal function is used to return a signal object of a specified signal. Its prototype is as follows:

func Signal(sig syscall.Signal) Signal

Among them, the sig parameter specifies a system Call the signal corresponding to the number, for example, SIGINT represents an interrupt signal. The returned Signal object can be used, for example, using the Wait method to wait for the arrival of the signal.

The Notify function is used to register the signal processing function of the process. When a specified signal arrives, the corresponding function will be called for processing. The function prototype is as follows:

func Notify(c chan<- os.Signal, sig ...os.Signal)

Among them, the c parameter is the channel used to receive the incoming signal, and the sig parameter Specify the signal object that needs to be registered. The sample code is as follows:

package main

import (
    "fmt"
    "os"
    "os/signal"
    "syscall"
    "time"
)

func main() {
    c := make(chan os.Signal, 1)
    signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
    go func() {
        s := <-c
        fmt.Println("received signal:", s)
        os.Exit(1)
    }()

    fmt.Println("Start working...")
    for {
        fmt.Println("working...")
        time.Sleep(time.Second * 1)
    }
}

In the above sample program, we add the SIGINT and SIGTERM signals to the signal pipeline by calling the Notify function. When the waiting signal is received, the program will exit immediately. Through signal processing, we can control the running and ending of the program very flexibly.

Summary

This article introduces process control and signal processing in Go language. In Go language, process startup and control can be achieved by calling the os library and exec library. At the same time, you can also use Signal handling mechanism to implement inter-process communication and control. Mastering process control and signal processing allows us to more flexibly control the running and exit of the program.

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