unsigned long and uint32_t?

Question

I'm studying socket programming and I learned inet_addr function. But I'm confused how can I handle in_addr_t type.

inet_addr function returns in_addr_t type which is uint32_t, then do I have to use uint32_t type variable to handle it?

In the book, example handles it as unsigned long type, but I don't understand why this way is used.

unsigned long conv_addr = inet_addr(addr1); // unsigned long == uint32_t?

Answer 1

You do not have to use uint32_t to handle the value returned from inet_addr. You can use any type that can represent any value that might be returned or that you might use in a calculation. But why not use the uint32_t or the in_addr_t type?

Answer 2

You may use long type also for inet_addr() function since most of the architecture use 32 bits(4 bytes) for long type but it is not always applicable

Some architecture use 64 bits for long type.. LP64 convention use 64 bits for long type

But the size of uint32_t is always 32 bits independent of convention the compiler is following.

If you are writing programs using MSVC, it uses 32 bits for long type.

For gcc, it depends on computer hardware and implementation of GCC.

It is safe to use unsigned long for assigning to the return type of inet_addr() when you are confident with long size is 32 bits.

Recommended to use uint32_t(aka unsigned 32 bit memory) for inet_addr(), so you don't need to care about the size of long type at all...