npm package: @stdlib/napi-argv-dataview-cast
Description: Convert a Node-API value corresponding to a DataView to a pointer having a specified data type.
Author: The Stdlib Authors
Latest version: 0.1.1

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    About stdlib...
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  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
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# ARGV_DATAVIEW_CAST

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Convert a Node-API value corresponding to a DataView to a pointer having a specified data type.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/napi-argv-dataview-cast
```

</section>

<section class="usage">

## Usage

```javascript
var headerDir = require( '@stdlib/napi-argv-dataview-cast' );
```

#### headerDir

Absolute file path for the directory containing header files for C APIs.

```javascript
var dir = headerDir;
// returns <string>
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

</section>

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<section class="examples">

## Examples

```javascript
var headerDir = require( '@stdlib/napi-argv-dataview-cast' );

console.log( headerDir );
// => <string>
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

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<section class="intro">

</section>

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<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#include "stdlib/napi/argv_dataview_cast.h"
```

#### STDLIB_NAPI_ARGV_DATAVIEW_CAST( env, X, type, argv, index )

Macro for converting an add-on callback argument corresponding to a DataView to a pointer having a specified data type.

```c
struct complex128 {
    double re;
    double im;
};

static void fcn( const struct complex128 *X, struct complex128 *Y ) {
    Y->re = X->re + Y->re;
    Y->im = X->im + Y->im;
}

// ...

static napi_value addon( napi_env env, napi_callback_info info ) {
    // Retrieve add-on callback arguments:
    STDLIB_NAPI_ARGV( env, info, argv, argc, 2 );

    // Convert the first argument to a C type:
    STDLIB_NAPI_ARGV_DATAVIEW_CAST( env, X, struct complex128, argv, 0 );

    // Convert the second argument to a C type:
    STDLIB_NAPI_ARGV_DATAVIEW_CAST( env, Y, struct complex128, argv, 1 );

    // ...

    fcn( X, Y );
}
```

The macro expects the following arguments:

-   **env**: environment under which the callback is invoked.
-   **X**: output variable name.
-   **type**: output variable type.
-   **argv**: name of the variable containing add-on callback arguments.
-   **index**: argument index.

</section>

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</section>

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<!-- C API usage examples. -->

<section class="examples">

</section>

<!-- /.examples -->

</section>

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* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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