阅读TCP某物,知道server并关闭sockfd当写两次,会产生SIGPIPE信号,假如不治疗,默认将挂起server
弄个小样本试验:
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <signal.h>
#define ERR_EXIT(m) \
do { \
perror(m);\
exit(EXIT_FAILURE);\
}while(0) void handle(int arg)
{
printf("sigpipe\n");
}
int main(int argc, const char *argv[])
{
signal(SIGPIPE, handle);//SIGPIPE信号的处理
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(sockfd == -1)
ERR_EXIT("socket");
struct sockaddr_in seraddr;
seraddr.sin_family = AF_INET;
seraddr.sin_port = htons(8888);
seraddr.sin_addr.s_addr = inet_addr("127.0.0.1") ;
socklen_t len = sizeof(seraddr);
if(-1 == (bind(sockfd, (struct sockaddr*)&seraddr, len)))
ERR_EXIT("bind");
if(listen(sockfd, 3) == -1)
ERR_EXIT("listen"); int clientfd = accept(sockfd, NULL, NULL);
printf("client\n");
while(1)
{
sleep(3);
printf("hello\n");
write(clientfd, "hello", sizeof("hello"));
}
return 0;
}
client使用telnet连接
发现:
当client关闭后,server端还会写两次后。就会收到SIGPIPE信号,兴许继续会收到此信号
telnet localhost 8888
--》client:
syswj@host ~]$ telnet localhost 8888
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hello
hello
hello
^]
telnet> Connection closed.
server信息:
➜ mianshi git:(master) ✗ ./a.out
client
hello
hello
hello
hello //-》对方会发送一个RST复位报文
hello
sigpipe
hello
sigpipe //-->是因为write导致的
hello
sigpipe
hello
sigpipe
^C
能够看到是在client关闭后,再发送 第2个信息后才收到的SIFPIPE信号
兴许发送仍然会收到SIGPIPE信号
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