我用例子来说明：只是一个模拟，我自己做的 假的 bgwriter.c
[root@localhost test]# cat bgwriter.c #include<stdio.h> #include<stdlib.h> #include<signal.h> #include "bgwriter.h" #include "guc.h" //some conditions make it change, eg:signal int BgWriterDelay=100; void sighandler(int sig); int main() { signal(SIGHUP,sighandler); for (;;) { sleep(1); } } void sighandler(int sig) { changeDelay(); fprintf(stderr,"BgWriterDelay is now %d.\n",BgWriterDelay); //here I just want to demo, so close it exit(0); } [root@localhost test]# ///////////////////////////////////////////////////////////////// 下面的 "bgwriter.h" and "guc.h" and "guc.c"，也都是假的。只是为了模拟。
///////////////////////////////////////////////////////////////// [root@localhost test]# cat bgwriter.h extern int BgWriterDelay; [root@localhost test]# [root@localhost test]# cat guc.h extern void changeDelay(); [root@localhost test]#cat guc.c #include "bgwriter.h" void changeDelay() { //to simulate reading configuration file etc. BgWriterDelay=500; } [root@localhost test]# ///////////////////////////////////////////////////////////////// 给 SIGHUP 信号 [root@localhost test]# gcc bgwriter.c guc.c -o bgwriter.o [root@localhost test]# ./bgwriter.o [root@localhost ~]# ps -ef|grep bgwriter.o root 5475 5297 0 15:08 pts/6 00:00:00 ./bgwriter.o root 5500 5479 0 15:08 pts/7 00:00:00 grep bgwriter.o [root@localhost ~]# kill -s SIGHUP 5475 [root@localhost ~]# BgWriterDelay is now 500. [root@localhost test]#
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本文转自健哥的数据花园博客园博客，原文链接：http://www.cnblogs.com/gaojian/archive/2012/10/31/2747388.html，如需转载请自行联系原作者
