about ip.h

[alicornio]

hello all 

i have a problem when i try to compile a code. this is the error: 

in file included from packetCreate.c:5: 
/usr/include/netinet/ip.h:160: error: systax error before "n_long" 
/usr/include/netinet/ip.h:163: error: systax error before "n_long" 

then searching in the ip.h i change "n_long" to "u_long" and the code was 
compiled well. 

my questions are: why i need to modify this ? i search for "n_long" in 
types.h but i can't find it, where is "n_long"? seaching on the 
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/ip.h i saw which all 
versions of ip.h have "n_long", then "n_long" (not u_long) is the correct 
form, right? 

sorry for my bad english :-) 

thanks all 

thiago_cabeludo