nn_send.3compat.adoc

nn_send(3compat)

NAME

nn_send - send data (compatible API)

SYNOPSIS

#include <nanomsg/nn.h>

int nn_send(int sock, const void *data, size_t size, int flags)

DESCRIPTION

The nn_send() function creates a message containing data (of size size), and sends using the socket sock.

Note	This function is provided for API compatibility with legacy libnanomsg. Consider using the relevant modern API instead.

If size has the special value NN_MSG, then a zero-copy operation is performed. In this case, data points not to the message content itself, but instead is a pointer to the pointer, an extra level of pointer indirection. The message must have been previously allocated by nn_allocmsg() or nn_recvmsg(), using the same `NN_MSG size. In this case, the ownership of the message shall remain with the caller, unless the function returns 0, indicating that the function has taken responsibility for delivering or disposing of the message.

The flags field may contain the special flag NN_DONTWAIT. In this case, if the socket is unable to accept more data for sending, the operation shall not block, but instead will fail with the error EAGAIN.

Note	The send operation is performed asynchronously, and may not have completed before this function returns control to the caller.

RETURN VALUES

This function returns the number of bytes sent on success, and -1 on error.

ERRORS

EAGAIN	The operation would block.
EBADF	The socket sock is not open.
EFSM	The socket cannot send in this state.
ENOTSUP	This protocol cannot send.
ETIMEDOUT	Operation timed out.

SEE ALSO

nn_errno(3compat), nn_recv(3compat), nn_sendmsg(3compat), nn_socket(3compat), nn_compat(3compat), nng(7)