nng_aio_set_iov3
Set scatter/gather vector
Usage
#include <nng/nng.h> int nng_aio_set_iov(nng_aio *aio, unsigned int niov, nng_iov *iov);
Overview
The nng_aio_set_iov() function sets a scatter/gather vector iov on the handle aio.
The iov is a pointer to an array of niov nng_iov structures, which have the following definition:
typedef struct nng_iov {
void * iov_buf;
size_t iov_len;
};
The iov is copied into storage in the aio itself, so that callers may use stack allocated nng_iov structures. The values pointed to by the iov_buf members are not copied by this function though.
A maximum of four (4) nng_iov members may be supplied.
Note
Earlier versions of the library could accept longer scatter-gather lists. However, no known consumers have ever needed a scatter-gather list longer than 4 vectors. As a result, the implementation limit was reduced, and heap allocations which could fail were removed.
Return values
This function returns 0 on success, and non-zero otherwise.
Errors
NNG_EINVAL
Value of specified niov is too large.