UNIX for Dummies Questions & Answers

Hi All,

I am running a short program on the effects of host-to-network and network-to-host functions. The following is part of my code:

int a = 384;
printf("Used htons with a, getting: %x Hex and %d Numeral\n", htons(a), htons(a));
printf("Used ntohs with a, getting: %x Hex and %d Numeral\n", ntohs(a), ntohs(a));
printf("Used htons(ntohs()) with a, getting: %x Hex and %d Numeral\n", htons(ntohs(a)), htons(ntohs(a)));
printf("Used ntohs(htons()) with a, getting: %x Hex and %d Numeral\n", ntohs(htons(a)), ntohs(htons(a)));

The following are the results:

Used htons with a, getting: 8001 Hex and 32769 Numeral
Used ntohs with a, getting: 8001 Hex and 32769 Numeral
Used htons(ntohs()) with a, getting: 180 Hex and 384 Numeral
Used ntohs(htons()) with a, getting: 180 Hex and 384 Numeral

I am using the program on a little-endian machine. I understand how 8001H and 32769 are derived but why are the first 2 results the same??

Unless I missed something:
1.network default is big endian
2.those calls translate from the endianness of the box to network default

Assuming you used them correctly, they indicate your system is in network byte order.
It may be that in your unistd.h there is _SC_KERNEL_IS_BIGENDIAN defined. That will tell you what the C compiler thinks about system endianness, anyway.

What OS & platform?