main/syscalls/handle_check_valid.md

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# zx_handle_check_valid

## Summary

Checks a handle's validity.

## Declaration

```c
#include <zircon/syscalls.h>

zx_status_t zx_handle_check_valid(zx_handle_t handle);
```

## Description

Checks if *handle* is a valid handle value referring to a valid handle.

## Rights

None.

## Return value

`zx_handle_check_valid()` returns `ZX_OK` if *handle* is valid.

## Errors

`ZX_ERR_INVALID_ARGS`  The value *handle* is ZX_HANDLE_INVALID (0).

`ZX_ERR_OUT_OF_RANGE`  One of the bits in ZX_HANDLE_FIXED_BITS_MASK (0b11) is
 0. Values in this range are never valid handle values.
 See [handles](/docs/concepts/kernel/handles.md) for more details.

`ZX_ERR_NOT_FOUND`  The value *handle* is structurally valid but does not refer
 to a valid handle. For example, the handle value could refer to a handle that has
 been closed or it could be a valid bit pattern that has not been allocated in
 the calling process' handle table.