| nn_allocmsg(3) |
| ============== |
| |
| NAME |
| ---- |
| nn_allocmsg - allocate a message |
| |
| |
| SYNOPSIS |
| -------- |
| *#include <nanomsg/nn.h>* |
| |
| *void *nn_allocmsg (size_t 'size', int 'type');* |
| |
| |
| DESCRIPTION |
| ----------- |
| Allocate a message of the specified 'size' to be sent in zero-copy fashion. |
| The content of the message is undefined after allocation and it should be filled |
| in by the user. While linknanomsg:nn_send[3] and linknanomsg:nn_sendmsg[3] allow |
| to send arbitrary buffers, buffers allocated using _nn_allocmsg()_ can be more |
| efficient for large messages as they allow for using zero-copy techniques. |
| |
| 'type' parameter specifies type of allocation mechanism to use. Zero is the |
| default one, however, individual transport mechanisms may define their |
| own allocation mechanisms, such as allocating in shared memory or allocating |
| a memory block pinned down to a physical memory address. Such allocation, |
| when used with the transport that defines them, should be more efficient |
| than the default allocation mechanism. |
| |
| |
| RETURN VALUE |
| ------------ |
| If the function succeeds pointer to newly allocated buffer is returned. |
| Otherwise, NULL is returned and 'errno' is set to to one of the values |
| defined below. |
| |
| |
| ERRORS |
| ------ |
| *EINVAL*:: |
| Supplied allocation 'type' is invalid. |
| *ENOMEM*:: |
| Not enough memory to allocate the message. |
| |
| |
| EXAMPLE |
| ------- |
| |
| ---- |
| void *buf = nn_allocmsg (12, 0); |
| memcpy (buf, "Hello world!", 12); |
| nn_send (s, &buf, NN_MSG, 0); |
| ---- |
| |
| |
| SEE ALSO |
| -------- |
| linknanomsg:nn_freemsg[3] |
| linknanomsg:nn_reallocmsg[3] |
| linknanomsg:nn_send[3] |
| linknanomsg:nn_sendmsg[3] |
| linknanomsg:nanomsg[7] |
| |
| AUTHORS |
| ------- |
| Martin Sustrik <sustrik@250bpm.com> |
| |
