error: dereferencing pointer to incomplete type in C
 

I am getting following compilation errors in gcc. Anyone please help me in finding what is wrong?
$ gcc -c recv_v4.c
recv_v4.c: In function `recv_v4':
recv_v4.c:42: error: dereferencing pointer to incomplete type
recv_v4.c:42: error: `ICMP_TIMXCEED' undeclared (first use in this function)
recv_v4.c:42: error: (Each undeclared identifier is reported only once
recv_v4.c:42: error: for each function it appears in.)
recv_v4.c:42: error: dereferencing pointer to incomplete type
recv_v4.c:42: error: `ICMP_TIMXCEED_INTRANS' undeclared (first use in this function)
recv_v4.c:59: error: dereferencing pointer to incomplete type
recv_v4.c:59: error: `ICMP_UNREACH' undeclared (first use in this function)
recv_v4.c:72: error: dereferencing pointer to incomplete type
recv_v4.c:72: error: `ICMP_UNREACH_PORT' undeclared (first use in this function)
recv_v4.c:75: error: dereferencing pointer to incomplete type
recv_v4.c:82: error: dereferencing pointer to incomplete type
recv_v4.c:82: error: dereferencing pointer to incomplete type

Following is the code:

trace.h

I have tried and worked for me. So I suggest you to type gcc -E rec_v4.c > rec_v4.i and look at that rec_v4.i file, maybe it will give you a tip where is it lost. I do not know what os you have, maybe a define solves it.

I am using CYGWIN and Windows XP Professional OS.

In my <netinet/ip_icmp.h> you need to have __USE_BSD defined to get struct icmp and the macros you're using.
Kevin Barry

I defined __USE_BSD in ip_icmp.h. But still having same errors.

Oh, no! Do not touch that file. gcc -D__USE_BSD -c recv_v4.c would be the way, but actually I cannot check if it solves your problem.

thanks pan64.

Yes, I should have been more explicit.
Kevin Barry

error: dereferencing pointer to incomplete type
 

i am working on my client/server chat program and i get "error: dereferencing pointer to incomplete type" when i compile my client.c.
Here is my code:

#include <stdio.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <string.h>
#include <stdlib.h>
#include <netdb.h>
#include <unistd.h>
#include <signal.h>
#include <time.h>

int main(int argc,char *argv[])
{
struct sockaddr_in clientaddr;
pid_t pid;
int clientfd,sendbytes;
struct hostent *host;
char *buf,*buf_r;

if(argc < 4)
{
printf("usage:\n");
printf("%s host port name\n",argv[0]);
exit(1);
}

host = gethostbyname(argv[1]);
if((clientfd = socket (AF_INET,SOCK_STREAM,0)) == -1)
{
perror("socket\n");
exit(1);
}
clientaddr.sin_family = AF_INET;
clientaddr.sin_port = htons((uint16_t)atoi(argv[2]));
clientaddr.sin_addr = *((struct in_addrr *) host->h_addr);
bzero(&(clientaddr.sin_zero),0);
if(connect(clientfd,(struct sockaddr *)&clientaddr,sizeof(struct sockaddr)) == -1)
{
perror("connect\n");
exit(1);
}

buf=(char *)malloc(120);
memset(buf,0,120);

buf_r=(char *)malloc(100);

if( recv(clientfd,buf,100,0) == -1)
{
perror("recv: ");
exit(1);
}
printf("\n%s\n",buf);

pid = fork();

while(1)
{
if(pid > 0)
{
//get_cur_time(time_str);

strcpy(buf,argv[3]);
strcat(buf,":");
memset(buf_r,0,100);
//gets(buf_r);
fgets(buf_r,100,stdin);
strncat(buf,buf_r,strlen(buf_r)-1);
//strcat(buf,time_str);
//printf("---%s\n",buf);
if((sendbytes = send(clientfd,buf,strlen(buf),0)) == -1)
{
perror("send\n");
exit(1);
}
}
else if(pid == 0)
{
memset(buf,0,1000);
if(recv(clientfd,buf,100,0) <=0)
{
perror("recv:");
close(clientfd);
raise(SIGSTOP);
exit(1);
}
printf("%s\n",buf);
}
else
perror("fork");
}
close(clientfd);
return 0;
}

Please help me find solution for this. Thank you.

please open a new thread for your problem and also please use [code]here comes your code[/code] to keep formatting, and post the full error message.
Actually the real error message was:
you made a typo in line 36:
clientaddr.sin_addr = *((struct in_addrr *) host->h_addr);
so, just remove that r