why printf() don't work?

[Tom Marchand]

trying putting newlines in the strings like this: 



   "receive overflow\n" 






----- Original Message ----- 
From: "Edward King" <zhangsc at neusoft.com> 
To: freebsd-questions at freebsd.org 
Sent: Monday, January 5, 2009 2:29:23 AM GMT -05:00 US/Canada Eastern 
Subject: why printf() don't work? 

I use FreeBSD7.0,and use signal,like follows: signal(SIGHUP,sig_hup); signal(SIGIO,sig_io); when I run call following code,it can run,but I find a puzzled question,it should print some information,such as printf("execute main()") will print execute main(),but in fact,printf fuction print none!!! Why printf function do not go work? my code is follows: #include "sys/ioctl.h" #include "unp.h" static int sockfd; #define QSIZE 8 #define MAXDG 4096 typedef struct{ void *dg_data; size_t dg_len; struct sockaddr *dg_sa; socklen_t dg_salen; }DG; static DG dg[QSIZE]; static long cntread[QSIZE+1]; static int iget; static int iput; static int nqueue; static socklen_t clilen; static void sig_io(int); static void sig_hup(int); int main(int argc,char **argv){ printf("execute main()"); int sockfd; struct sockaddr_in servaddr,cliaddr; sockfd=socket(AF_INET,SOCK_DGRAM,0); bzero(&servaddr,sizeof(servaddr)); servaddr.sin_family=AF_INET; servaddr.sin_addr.s_addr=htonl(INADDR_ANY); servaddr.sin_port=htons(SERV_PORT); bind(sockfd,(SA *)&servaddr,sizeof(servaddr)); dg_echo(sockfd,(SA *)&cliaddr,sizeof(cliaddr)); } void dg_echo(int sockfd_arg,SA *pcliaddr,socklen_t clilen_arg){ printf("called dg_echo"); int i; const int on=1; sigset_t zeromask,newmask,oldmask; sockfd=sockfd_arg; clilen=clilen_arg; for(i=0;i =QSIZE) iget=0; sigprocmask(SIG_BLOCK,&newmask,&oldmask); nqueue--; } } static void sig_io(int signo){ printf("sig_io called"); ssize_t len; int nread; DG *ptr; for(nread=0;;){ if(nqueue>=QSIZE) err_quit("receive overflow"); ptr=&dg[iput]; ptr->dg_salen=clilen; len=recvfrom(sockfd,ptr->dg_data,MAXDG,0,ptr->dg_sa,&ptr->dg_salen); if(len<0){ if(errno==EWOULDBLOCK) break; else err_sys("recvfrom error"); } ptr->dg_len=len; nread++; nqueue++; if(++iput>=QSIZE) iput=0; } cntread[nread]++; } static void sig_hup(int signo){ printf("sig_hup called"); int i; for(i=0;i<=QSIZE;i++) printf("cntread[%d]=%ld\n",i,cntread[i]); } --------------------------------------------------------------------------------------------------- Confidentiality Notice: The information contained in this e-mail and any accompanying attachment(s) is intended only for the use of the intended recipient and may be confidential and/or privileged of Neusoft Corporation, its subsidiaries and/or its affiliates. If any reader of this communication is not the intended recipient, unauthorized use, forwarding, printing, storing, disclosure or copying is strictly prohibited, and may be unlawful.If you have received this communication in error,please immediately notify the sender by return e-mail, and delete the original message and all copies from your system. Thank you. --------------------------------------------------------------------------------------------------- 
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