Resolve bind error bind:address already in use

Handling of BIND errors:
Bind:address already in use

Cause: The operating system does not immediately release the port

Resolution one: Wait for a period of time to run the network program

Resolution two: Set by setsockopt, the key code is as follows.

1         //resolves an issue in which a wait_time after close causes bind to fail2     intval =1;3     intret = setsockopt (SFD,SOL_SOCKET,SO_REUSEADDR, (void*) &val,sizeof(int));4     if(ret = =-1)5     {6printf"setsockopt");7Exit1);8}

Example: Taking a multi-process concurrent server as an example

1#include <stdio.h>2#include <stdlib.h>3#include <string.h>4 5#include <sys/types.h>6#include <sys/socket.h>7#include <netinet/inch.h>8#include <arpa/inet.h>9#include <signal.h>Ten  One #definePORT 7788 A  - intinit_tcp () - { the     //1. Create Sockets-Set Protocol -     intSFD = socket (Af_inet,sock_stream,0); -     if( -1==SFD) -     { +Perror ("Socket"); -Exit (-1); +     } A     //2. Resolve an issue with wait_time after close that causes bind to fail at     intval =1; -     intret = setsockopt (SFD,SOL_SOCKET,SO_REUSEADDR, (void*) &val,sizeof(int)); -     if(ret = =-1) -     { -printf"setsockopt"); -Exit1); in     } -     //3. Bind IP and Port to     structsockaddr_in saddr; +saddr.sin_family =af_inet; -SADDR.SIN_ADDR.S_ADDR =Inaddr_any; theSaddr.sin_port =htons (PORT); *ret = bind (SFD, (structSOCKADDR *) &saddr,sizeof(SADDR)); $     if(ret = =-1)Panax Notoginseng     { -printf"Bind"); theExit1); +     } A     //4. Monitoring theRET = Listen (SFD,5); +     if(ret = =-1) -     { $printf"Listen"); $Exit1); -     } -printf"Server is ready ... \ n"); the      -     returnsfd;Wuyi } the  - voidDeal_communication (intCfD) Wu { -     Charbuf[ -] = {' /'}; About      while(1) $     { -memset (BUF,' /',sizeof(BUF)); -Recv (Cfd,buf,sizeof(BUF),0); -printf"Client say:%s\n", buf); ASend (Cfd,buf,strlen (BUF),0); +         if(STRNCMP (BUF,"quit",4) ==0) the          Break;  -     } $  the     return ; the } the  the  - intMain () in { the     //1. Initialize (create socket socket/address multiplexing +bind/listen) the     intSFD =init_tcp (); About     //2. Concurrent processing client (accept/fork) 2-2 communication the      while(1) the     { the         intCFD =Accept (sfd,null,null); +         if(cfd = =-1) -         { thePerror ("Accept");BayiExit1); the         } the          -         //fork-create a child process -         if(fork () = =0) the         { the deal_communication (CFD); the Close (CFD); theExit0); -         } the Close (CFD); the signal (SIGCHLD,SIG_DFL); the     }94 Close (SFD); the     return 0; the}

Resolve bind error bind:address already in use