# binary
> C APIs for registering a Node-API module exporting interfaces for invoking binary numerical functions.
## Usage
```javascript
var headerDir = require( '@stdlib/math/base/napi/binary' );
```
#### headerDir
Absolute file path for the directory containing header files for C APIs.
```javascript
var dir = headerDir;
// returns
```
## Examples
```javascript
var headerDir = require( '@stdlib/math/base/napi/binary' );
console.log( headerDir );
// =>
```
* * *
## C APIs
### Usage
```c
#include "stdlib/math/base/napi/binary.h"
```
#### stdlib_math_base_napi_dd_d( env, info, fcn )
Invokes a binary function accepting and returning double-precision floating-point numbers.
```c
#include
// ...
static double add( const double x, const double y ) {
return x + y;
}
// ...
/**
* Receives JavaScript callback invocation data.
*
* @param env environment under which the function is invoked
* @param info callback data
* @return Node-API value
*/
napi_value addon( napi_env env, napi_callback_info info ) {
return stdlib_math_base_napi_dd_d( env, info, add );
}
// ...
```
The function accepts the following arguments:
- **env**: `[in] napi_env` environment under which the function is invoked.
- **info**: `[in] napi_callback_info` callback data.
- **fcn**: `[in] double (*fcn)( double, double )` binary function.
```c
void stdlib_math_base_napi_dd_d( napi_env env, napi_callback_info info, double (*fcn)( double, double ) );
```
#### stdlib_math_base_napi_ff_f( env, info, fcn )
Invokes a binary function accepting and returning single-precision floating-point numbers.
```c
#include
// ...
static float addf( const float x, const float y ) {
return x + y;
}
// ...
/**
* Receives JavaScript callback invocation data.
*
* @param env environment under which the function is invoked
* @param info callback data
* @return Node-API value
*/
napi_value addon( napi_env env, napi_callback_info info ) {
return stdlib_math_base_napi_ff_f( env, info, addf );
}
// ...
```
The function accepts the following arguments:
- **env**: `[in] napi_env` environment under which the function is invoked.
- **info**: `[in] napi_callback_info` callback data.
- **fcn**: `[in] float (*fcn)( float, float )` binary function.
```c
void stdlib_math_base_napi_ff_f( napi_env env, napi_callback_info info, float (*fcn)( float, float ) );
```
#### STDLIB_MATH_BASE_NAPI_MODULE_DD_D( fcn )
Macro for registering a Node-API module exporting an interface for invoking a binary function accepting and returning double-precision floating-point numbers.
```c
static double add( const double x, const double y ) {
return x + y;
}
// ...
// Register a Node-API module:
STDLIB_MATH_BASE_NAPI_MODULE_DD_D( add );
```
The macro expects the following arguments:
- **fcn**: `double (*fcn)( double, double )` binary function.
When used, this macro should be used **instead of** `NAPI_MODULE`. The macro includes `NAPI_MODULE`, thus ensuring Node-API module registration.
#### STDLIB_MATH_BASE_NAPI_MODULE_FF_F( fcn )
Macro for registering a Node-API module exporting an interface for invoking a binary function accepting and returning single-precision floating-point numbers.
```c
static float addf( const float x, const float y ) {
return x + y;
}
// ...
// Register a Node-API module:
STDLIB_MATH_BASE_NAPI_MODULE_FF_F( addf );
```
The macro expects the following arguments:
- **fcn**: `float (*fcn)( float, float )` binary function.
When used, this macro should be used **instead of** `NAPI_MODULE`. The macro includes `NAPI_MODULE`, thus ensuring Node-API module registration.
### Notes
- The C-API functions expect that the callback `info` argument provides access to the following JavaScript arguments:
- `x`: input value.
- `y`: input value.