Hi All,
int bind(int SOCKFD, struct sockaddr *MYADDR, int ADDRLEN);
In the above system call, the third argument is the length of socket address structure.
My question is why we need third argument? since we are passing second parameter as pointer to socket address structure, so it can calculate itself the length of the structure.
Thanks,
Manjunath
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Recognized Expert Moderator Expert
No you can not calculate the length of anything based on a pointer to it. In particular the sockaddr structure contents may be different depending on the type of network address being supplied, e.g. IVv4 or IPv6 to name two.
It you google struct sockaddr you will find that this is a generic pointer to a family of structures which are all different specifying network addresses in different protocols.
The size parameter therefore lets the function use this pointer while ensuring that it does not cause undefined behaviour by accessing out of bounds data.
Thanks a lot, The answer make my confusion clear.
Thanks,
Manjunath
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