Error:dereferencing pointer to incomplete type solution

Problem:

The following compile error occurred while compiling the program:

dingq@u1110-120628:~/hwsvn/2sw/1prj_linux/pdu/src/branches/pdu-isocket/isocket$ gcc-o tcpclient tcpclient.c 
tcpclient.c:in function ' main ':
tcpclient.c:59:46:error:dereferencing pointer to incomplete type

Source code is:

	Set params of sockaddr_in instances
	serv_addr.sin_family = af_inet;
	Serv_addr.sin_port = htons (port);
	SERV_ADDR.SIN_ADDR = * ((struct in_addr*) host->h_addr);
	Bzero (& (Serv_addr.sin_zero), 8);

Solution:

1. Put the dog search, see that the type is not completely caused, only type definition, and no type declaration;

Further, it is the lack of the inclusion of some of the header documents that caused the problem;

2. include header file <netdb.h> recompile, error disappears.

Solve the problem.