vmo_read - read bytes from the VMO
#include <zircon/syscalls.h> zx_status_t zx_vmo_read(zx_handle_t handle, void* buffer, uint64_t offset, size_t buffer_size);
vmo_read() attempts to read exactly buffer_size bytes from a VMO at offset.
buffer pointer to a user buffer to read bytes into.
buffer_size number of bytes to attempt to read. buffer buffer should be large enough for at least this many bytes.
zx_vmo_read() returns ZX_OK on success, and exactly buffer_size bytes will have been written to buffer. In the event of failure, a negative error value is returned, and the number of bytes written to buffer is undefined.
ZX_ERR_BAD_HANDLE handle is not a valid handle.
ZX_ERR_WRONG_TYPE handle is not a VMO handle.
ZX_ERR_ACCESS_DENIED handle does not have the ZX_RIGHT_READ right.
ZX_ERR_INVALID_ARGS buffer is an invalid pointer or NULL.
ZX_ERR_OUT_OF_RANGE offset starts at or beyond the end of the VMO, or VMO is shorter than buffer_size.
ZX_ERR_BAD_STATE VMO has been marked uncached and is not directly readable.