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# zx_fifo_write
## NAME
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Write data to a fifo.
## SYNOPSIS
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```c
#include <zircon/syscalls.h>
zx_status_t zx_fifo_write(zx_handle_t handle,
size_t elem_size,
const void* data,
size_t count,
size_t* actual_count);
```
## DESCRIPTION
`zx_fifo_write()` attempts to write up to *count* elements
(`count * elem_size` bytes) from *data* to the fifo specified by *handle*.
Fewer elements may be written than requested if there is insufficient
room in the fifo to contain all of them. The number of
elements actually written is returned via *actual_count*.
The element size specified by *elem_size* must match the element size
that was passed into [`zx_fifo_create()`].
*actual_count* is allowed to be NULL. This is useful when writing
a single element: if *count* is 1 and `zx_fifo_write()` returns **ZX_OK**,
*actual_count* is guaranteed to be 1 and thus can be safely ignored.
It is not legal to write zero elements.
## RIGHTS
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*handle* must be of type **ZX_OBJ_TYPE_FIFO** and have **ZX_RIGHT_WRITE**.
## RETURN VALUE
`zx_fifo_write()` returns **ZX_OK** on success, and returns
the number of elements written (at least one) via *actual_count*.
## ERRORS
**ZX_ERR_BAD_HANDLE** *handle* is not a valid handle.
**ZX_ERR_WRONG_TYPE** *handle* is not a fifo handle.
**ZX_ERR_INVALID_ARGS** *data* is an invalid pointer or *actual_count*
is an invalid pointer.
**ZX_ERR_OUT_OF_RANGE** *count* is zero or *elem_size* is not equal
to the element size of the fifo.
**ZX_ERR_ACCESS_DENIED** *handle* does not have **ZX_RIGHT_WRITE**.
**ZX_ERR_PEER_CLOSED** The other side of the fifo is closed.
**ZX_ERR_SHOULD_WAIT** The fifo is full.
## SEE ALSO
- [`zx_fifo_create()`]
- [`zx_fifo_read()`]
<!-- References updated by update-docs-from-abigen, do not edit. -->
[`zx_fifo_create()`]: fifo_create.md
[`zx_fifo_read()`]: fifo_read.md