use gcc -E to debug the header file inclusion

#include
#ifndef _WIN32_WCE
#include
#endif

#ifdef _WIN32_WCE
#include
#include
#include
#include
#include
#define close(s) closesocket(s)
#elif WIN32
#include
#include
#include
#include
#define close(s) closesocket(s)
#else
#include
#include
#include
#include
#include
#endif

#include

#include
#include

// Generate the file that only processed by the cpp (C Preprocessor)
# gcc -E eXregister_api.c -o eXregister_api.c.preprocessor
The following file is generated by the above command
------------------------------------------------------------
# 1 "eXosip2.h" 1
# 28 "eXosip2.h" ==> the 28th row of eXosip2.h
# 1 "/usr/include/stdio.h" 1 3 4

# 29 "eXosip2.h" 2 ==> the 29th row of eXosip2.h

# 1 "/usr/include/errno.h" 1 3 4
# 32 "/usr/include/errno.h" 3 4

# 31 "eXosip2.h" 2 ==> the 31th row of eXosip2.h
# 47 "eXosip2.h" ==> the 47th row of eXosip2.h
# 1 "/usr/include/sys/types.h" 1 3 4
# 29 "/usr/include/sys/types.h" 3 4

# 48 "eXosip2.h" 2 ==> the 48th row of eXosip2.h
# 1 "/usr/include/sys/socket.h" 1 3 4
# 26 "/usr/include/sys/socket.h" 3 4

# 49 "eXosip2.h" 2 ==> the 49th row of eXosip2.h
# 1 "/usr/include/netinet/in.h" 1 3 4
# 24 "/usr/include/netinet/in.h" 3 4
# 1 "/usr/include/stdint.h" 1 3 4
# 27 "/usr/include/stdint.h" 3 4
# 1 "/usr/include/bits/wchar.h" 1 3 4
# 28 "/usr/include/stdint.h" 2 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 29 "/usr/include/stdint.h" 2 3 4
# 49 "/usr/include/stdint.h" 3 4

# 50 "eXosip2.h" 2 ==> the 50th row of eXosip2.h
# 1 "/usr/include/arpa/inet.h" 1 3 4
# 31 "/usr/include/arpa/inet.h" 3 4

# 51 "eXosip2.h" 2 ==> the 51th row of eXosip2.h
# 1 "/usr/include/netdb.h" 1 3 4
# 33 "/usr/include/netdb.h" 3 4
# 1 "/usr/include/rpc/netdb.h" 1 3 4
# 42 "/usr/include/rpc/netdb.h" 3 4
# 1 "/usr/lib/gcc/i386-redhat-linux/4.1.2/include/stddef.h" 1 3 4
# 43 "/usr/include/rpc/netdb.h" 2 3 4

# 52 "eXosip2.h" 2