Question

iov[0] = (struct iovec) {
    .iov_base = &req,
    .iov_len = sizeof(req)
};

I’m trying to convert a bit of code from the ss network utility to c++, and the above and similar keeps giving these errors:

main.cpp|83|error: expected primary-    expression before ‘struct’
main.cpp|83|error: expected ‘)’ before ‘struct’

Answer 1

C++ doesn’t support that syntax. Try this:

iovec iov[2];
iov[0].iov_base = &req;
iov[0].iov_len = sizeof req;
/* ... */

Or maybe:

iovec iov[] = {
    {
       &req, sizeof req
    },
    /* ... */
}

What you were trying is a C99 feature called “compound literals”. Also, the .iov_base thing is called a “designated initializer”.