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# copysignf

> Return a [single-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `y`.

<section class="usage">

## Usage

```javascript
var copysignf = require( '@stdlib/math/base/special/copysignf' );
```

#### copysignf( x, y )

Returns a [single-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `y`.

```javascript
var z = copysignf( -3.0, 10.0 );
// returns 3.0

z = copysignf( 3.0, -1.0 );
// returns -3.0

z = copysignf( 1.0, -0.0 );
// returns -1.0

z = copysignf( -3.0, -0.0 );
// returns -3.0

z = copysignf( -0.0, 1.0 );
// returns 0.0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   According to the [IEEE754][ieee754] standard, a `NaN` has a biased exponent equal to `255`, a significand greater than `0`, and a sign bit equal to **either** `1` **or** `0`. In which case, `NaN` may not correspond to just one but many binary representations. Accordingly, care should be taken to ensure that `y` is **not** `NaN`; otherwise, behavior may be indeterminate.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var randu = require( '@stdlib/random/base/randu' );
var copysignf = require( '@stdlib/math/base/special/copysignf' );

var x;
var y;
var z;
var i;

// Generate random numbers `x` and `y` and copy the sign of `y` to `x`...
for ( i = 0; i < 100; i++ ) {
    x = (randu()*100.0) - 50.0;
    y = (randu()*10.0) - 5.0;
    z = copysignf( x, y );
    console.log( 'x: %d, y: %d => %d', x, y, z );
}
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#include "stdlib/math/base/special/copysignf.h"
```

#### stdlib_base_copysignf( x, y )

Returns a [single-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `y`.

```c
float v = stdlib_base_copysignf( -3.0f, 10.0f );
// returns 3.0f

float v = stdlib_base_copysignf( 3.0f, -1.0f );
// returns -3.0f
```

The function accepts the following arguments:

-   **x**: `[in] float` number from which to derive a magnitude.
-   **y**: `[in] float` number from which to derive a sign.

```c
float stdlib_base_copysignf( const float x, const float y );
```

</section>

<!-- /.usage -->

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

<section class="notes">

</section>

<!-- /.notes -->

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

<section class="examples">

### Examples

```c
#include "stdlib/math/base/special/copysignf.h"
#include <stdio.h>

int main( void ) {
    const float x[] = { 3.0f, -3.0f, 0.0f, 0.0f/0.0f };

    float y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_copysignf( x[ i ], -3.0f );
        printf( "copysignf(%f, %f) = %f\n", x[ i ], -3.0f, y );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/math/base/special/copysign`][@stdlib/math/base/special/copysign]</span><span class="delimiter">: </span><span class="description">return a double-precision floating-point number with the magnitude of x and the sign of y.</span>
-   <span class="package-name">[`@stdlib/math/base/special/flipsignf`][@stdlib/math/base/special/flipsignf]</span><span class="delimiter">: </span><span class="description">return a single-precision floating-point number with the magnitude of x and the sign of x\*y.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985

<!-- <related-links> -->

[@stdlib/math/base/special/copysign]: https://github.com/stdlib-js/math/tree/main/base/special/copysign

[@stdlib/math/base/special/flipsignf]: https://github.com/stdlib-js/math/tree/main/base/special/flipsignf

<!-- </related-links> -->

</section>

<!-- /.links -->
