nn_sendmsg(3compat)

SYNOPSIS

#include <nanomsg/nn.h>
-
-int nn_sendmsg(int sock, const struct nn_msghdr *hdr, int flags);

DESCRIPTION

The nn_sendmsg() function sends the message described by hdr using the -socket sock.

- - - - - -

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

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.

The hdr points to a structure of type struct nn_msghdr, which has the -following definition:

struct nn_iovec {
-    void * iov_base;
-    size_t iov_len;
-};
-
-struct nn_msghdr {
-    struct nn_iovec *msg_iov;
-    int              msg_iovlen;
-    void *           msg_control;
-    size_t           msg_controllen;
-};

The msg_iov is an array of gather items, permitting the message -to be spread into different memory blocks. -There are msg_iovlen elements in this array, each of which -has the base address (iov_base) and length (iov_len) indicated.

For buffers allocated for zero copy -(such as by nn_allocmsg()), the value -of iov_base should be the address of the pointer to the buffer, -rather than the address of the buffer itself. -In this case, the value of iov_len should be NN_MSG, -as the length is inferred from the allocated message. -If the msg_iovlen field is NN_MSG, then this function will free -the associated buffer after it is done with it, if it returns successfully. -(If the function returns with an error, then the caller retains ownership -of the associated buffer and may retry the operation or free the buffer -at its choice.)

The values of msg_control and msg_controllen describe a buffer -of ancillary data to send the message. -This is currenly only useful to provide the message headers -used with raw mode sockets. -In all other circumstances these fields should be zero. -Details about this structure are covered in -nn_cmsg(3compat).

- - - - - -

- -	-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. -
-`EINVAL` -	- The hdr is invalid. -
-`ENOTSUP` -	- This protocol cannot send. -
-`ETIMEDOUT` -	- Operation timed out. -

nn_sendmsg(3compat) Manual Page

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

ERRORS

SEE ALSO