[SOLVED] htonl printing garbage value

Issue

The variable 'value' is uint32_t

    value = htonl(value);

    printf("after htonl  is %ld\n\n",value);

    This prints -201261056

    value = htons(value);

    printf("after htons  is %ld\n\n",value);

    This prints  62465

Please suggest what could be the reason?

Solution

I guess your input is 500, isn't it?

500 is 2**8+2**7+2**6+2**5+2**4+2**2 or 0x00 0x00 0x01 0xF4 in little endian order.

TCP/IP uses big endian. So after the htonl, the sequence is 0xF4 0x01 0x00 0x00.

If you print it as signed integer, since the first digit is 1, it is negative then. Negative numbers are regarded as complement, The value is -(2**27 + 2**25+2**24+2**23+2**22+2**21+2**20+2**19+2**18+2**17+2**16) == -201261056

Answered By - halfelf

Answer Checked By - Terry (WPSolving Volunteer)