I wrote a few code to test fork like following:
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
int DemoFork()
{
pid_t pid,par_pid;
par_pid = getpid();
pid = fork();
switch (pid) {
case -1: printf("failure!\n"); break;
case 0: printf("I am child!, parent is %d(\n",par_pid); break;
default: printf("my child is %d\n",pid); break;
}
for(; ; ) { /* do something here */ }
}and I wrote a routine to test structure size.
typedef char arr_name[8];
typedef struct
{
arr_name a;
int len;
}demostr;
int teststr(arr_name str)
{
demostr ab;
strncpy(ab.a,str,sizeof(str));
[B][I]printf("size of data type = %d,size of data = %d, size of input para = %d, a = %s",sizeof(arr_name), sizeof(ab.a), sizeof(str),ab.a);[/I][/B]
}then I wrote a main.
int main()
{
teststr();
DemoFork();
}after running, I use "ps -ef" to check, I found only parent Process is there and I cannot find the child process. If I removed teststr() call in the main(). the two process is there. Who meet such problem when using fork()?
thanks a lot.
New finding: I found the problem is printf() line in teststr, If I remove this line, there is no problem at all. But I don't know the reason, who can help to explain it?
thanks a lot.