npm package: @stdlib/napi-argv
Description: C utilities for retrieving Node-API add-on callback arguments.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    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

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

> C utilities for retrieving Node-API add-on callback arguments.

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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
```

</section>

<section class="usage">

## Usage

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

#### headerDir

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

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

</section>

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<section class="notes">

</section>

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<section class="examples">

## Examples

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

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.h"
```

#### STDLIB_NAPI_ARGV( env, info, argv, argc, nargs )

Macro for retrieving add-on callback arguments.

```c
#include <node_api.h>

// ...

static napi_value addon( napi_env env, napi_callback_info info ) {
    // Retrieve callback arguments:
    STDLIB_NAPI_ARGV( env, info, argv, argc, 6 );

    // ...
}
```

The macro expects the following arguments:

-   **env**: environment under which the callback is invoked.
-   **info**: callback data.
-   **argv**: variable name for storing argument values.
-   **argc**: variable name for storing the number of provided arguments.
-   **nargs**: expected number of arguments.

If the number of provided arguments does **not** equal the expected number of arguments, the macro's generated code raises an exception.

#### STDLIB_NAPI_ARGV_INDEX2ORDINAL( index )

Macro for converting an index to an ordinal numeral.

```c
STDLIB_NAPI_ARGV_INDEX2ORDINAL( 2 )
```

The macro expects the following arguments:

-   **index**: argument index value.

The first few ordinal numerals are as follows:

-   `STDLIB_NAPI_ARGV_INDEX2ORDINAL( 0 )`: "First".
-   `STDLIB_NAPI_ARGV_INDEX2ORDINAL( 1 )`: "Second".
-   `STDLIB_NAPI_ARGV_INDEX2ORDINAL( 2 )`: "Third".
-   `STDLIB_NAPI_ARGV_INDEX2ORDINAL( 3 )`: "Fourth".
-   `STDLIB_NAPI_ARGV_INDEX2ORDINAL( 4 )`: "Fifth".
-   ...
-   `STDLIB_NAPI_ARGV_INDEX2ORDINAL( 29 )`: "Thirtieth".

This macro can be useful when generating error messages which state which argument is invalid (e.g., "invalid argument. **First** argument must be a number." ).

</section>

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</section>

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<section class="examples">

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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<section class="main-repo" >

* * *

## 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

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

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

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