SYNOPSIS
#include <nng/nng.h>
int nng_msg_header_insert(nng_msg *msg, const void *val, size_t size);
int nng_msg_header_insert_u32(nng_msg *msg, uint32_t val32);DESCRIPTION
The nng_msg_header_insert() and nng_msg_header_insert_u32() functions
prepend data to the front of the headers of message msg, reallocating
if necessary.
The first function prepends size bytes, copying them from val. The
second function prepends the value val32 in network-byte order (big-endian).
RETURN VALUES
This function returns 0 on success, and non-zero otherwise.
ERRORS
NNG_ENOMEM-
Insufficient free memory exists.