> ## Documentation Index
> Fetch the complete documentation index at: https://prod-mint.classiq.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Mid-Circuit Measurement

<Warning>
  This feature is under development.
</Warning>

## Syntax

<Tabs>
  <Tab title="Python">
    **measure** **(** *quantum-var* **)**
  </Tab>

  <Tab title="Native">
    **measure** **(** *quantum-var* **)**
  </Tab>
</Tabs>

## Semantics

* A `measure` call receives a quantum variable of type `QBit` and returns a
  `CBool` value.
* In Qmod Native, when `measure` is called, it must be immediately be assigned
  to a local classical variable, e.g., `x = measure(q);`.
* Measurements are [run-time](/qmod-reference/language-reference/classical-variables#run-time-variables)
  values. Currently, `if` is the only control flow statements that supports
  run-time variables.
* Following the `measure` operation, any superposition state of its operand
  collapses to a computational-basis state corresponding to the classical
  measured result.

## Example

The following function implements the `RESET` gate using a mid-circuit
measurement.

<Tabs>
  <Tab title="Python">
    [comment]: DO_NOT_TEST

    ```python theme={null}
    from classiq import *


    @qfunc
    def reset(q: QBit):
        val = measure(q)
        if_(val, lambda: X(q))
    ```
  </Tab>

  <Tab title="Native">
    ```
    qfunc reset(q: qbit) {
      val: bool;
      val = measure(q);
      if (val) {
        X(q);
      }
    }
    ```
  </Tab>
</Tabs>