cc @ianlancetaylor

The SIGPIPE rules in the documentation only apply to a SIGPIPE signal that was raised by the kernel (due to a write to a broken pipe). They do not apply to a SIGPIPE sent via the kill system call.

NOTICE that, the signal actually raised by socket write (as i said at begin). You can reproduced it with socket write broken pipe.I just want to find a equal form. With gdb i find socket broken pipe and kill SIGPIPE both trigger raisebadsignal and they have the same call stack

@ianlancetaylor
Hi, I write a socket broke pipe example, just like the example above, uncomment raiseSigpipe in subThread, it will make program exit.

I think it's better to reopen the issue.

package main

/*
#include <pthread.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/socket.h>

void raiseSigpipe()
{
    char fake_buf[1024];

    int sock = socket(AF_INET, SOCK_STREAM, 0);
    struct sockaddr_in sa;
    memset(&sa, 0, sizeof(sa));
    sa.sin_family = AF_INET;
    sa.sin_addr.s_addr = inet_addr("127.0.0.1");
    sa.sin_port = htons(8989);
    connect(sock, (struct sockaddr *)&sa, sizeof(sa));
    send(sock, fake_buf, 1024, 0);
    sleep(2);
    send(sock, fake_buf, 1024, 0);
    send(sock, fake_buf, 1024, 0); // sigpipe
}

void *subThread(void *_)
{
    // raiseSigpipe();
    return NULL;
}

void test()
{
    pthread_t thread_id;
    pthread_create(&thread_id, NULL, subThread, NULL);
    pthread_join(thread_id, NULL);

    raiseSigpipe();
}
*/
import "C"

import (
	"net"
)

func main() {

	go func() {
		listener, _ := net.Listen("tcp", "127.0.0.1:8989")
		for {
			var d [1024]byte
			conn, _ := listener.Accept()
			conn.(*net.TCPConn).SetLinger(0)
			conn.Read(d[:])
			conn.Close()
		}
	}()

	C.test()

	// should not exit
	println("run")
	select {}
}

My apologies, you're right: the code does check whether a SIGPIPE was delivered to a Go thread or a C thread. I'll update the docs.

Change https://go.dev/cl/442415 mentions this issue: os/signal: document behavior of SIGPIPE on non-Go thread

Actually, signal hander defined in go can process the SIGPIPE raised in pthread thread. Is the behavior expected according to the doc?

... And why not make program also ignore SIGPIPE from C thread as all signal processed by go signal hander ?

We don't know what the C code is doing with SIGPIPE. There is no choice that is always correct. The current choice seems as good as any, and since we've had it for several years we may as well keep it.

If a Go program calls C code that doesn't want to get SIGPIPE, the C code install its own handler, perhaps SIG_IGN, for SIGPIPE.