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# zx_fifo_read
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Read data from a fifo.
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#include <zircon/syscalls.h>
zx_status_t zx_fifo_read(zx_handle_t handle,
size_t elem_size,
void* data,
size_t data_size,
size_t* actual_count);
`zx_fifo_read()` attempts to read up to *count* elements from the fifo
*handle* into *data*.
Fewer elements may be read than requested if there are insufficient
elements in the fifo to fulfill the entire request. The number of
elements actually read is returned via *actual_count*.
The element size specified by *elem_size* must match the element size
that was passed into [`zx_fifo_create()`].
*data* must have a size of at least `count * elem_size` bytes.
*actual_count* is allowed to be NULL. This is useful when reading
a single element: if *count* is 1 and `zx_fifo_read()` returns **ZX_OK**,
*actual_count* is guaranteed to be 1 and thus can be safely ignored.
It is not legal to read zero elements.
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*handle* must be of type **ZX_OBJ_TYPE_FIFO** and have **ZX_RIGHT_READ**.
`zx_fifo_read()` returns **ZX_OK** on success, and returns
the number of elements read (at least one) via *actual_count*.
**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_READ**.
**ZX_ERR_PEER_CLOSED** The other side of the fifo is closed.
**ZX_ERR_SHOULD_WAIT** The fifo is empty.
- [`zx_fifo_create()`]
- [`zx_fifo_write()`]
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