frexp(3) Library Functions Manual frexp(3)

# NOME

frexp, frexpf, frexpl - converte um número de ponto flutuante para componentes fracionário e inteiro

# BIBLIOTECA

Biblioteca matemática (libm, -lm)

# SINOPSE

`#include <math.h>`
```double frexp(double x, int *exp);
float frexpf(float x, int *exp);
long double frexpl(long double x, int *exp);```
Requisitos de macro de teste de recursos para o glibc (consulte feature_test_macros(7)):

frexpf(), frexpl():

```    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Desde o glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE```

# DESCRIÇÃO

These functions are used to split the number x into a normalized fraction and an exponent which is stored in exp.

# VALOR DE RETORNO

These functions return the normalized fraction. If the argument x is not zero, the normalized fraction is x times a power of two, and its absolute value is always in the range 1/2 (inclusive) to 1 (exclusive), that is, [0.5,1).

If x is zero, then the normalized fraction is zero and zero is stored in exp.

If x is a NaN, a NaN is returned, and the value of *exp is unspecified.

If x is positive infinity (negative infinity), positive infinity (negative infinity) is returned, and the value of *exp is unspecified.

# ERROS

Ocorre nenhum erro.

# ATRIBUTOS

Para uma explicação dos termos usados nesta seção, consulte attributes(7).

 Interface Atributo Valor frexp(), frexpf(), frexpl() Thread safety MT-Safe

C11, POSIX.1-2008.

# HISTÓRICO

C99, POSIX.1-2001.

A variante retornando double também está de acordo com SVr4, 4.3BSD, C89.

# EXEMPLOS

The program below produces results such as the following:

```\$ ./a.out 2560
frexp(2560, &e) = 0.625: 0.625 * 2^12 = 2560
\$ ./a.out -4
frexp(-4, &e) = -0.5: -0.5 * 2^3 = -4```

## Fonte do programa

```#include <float.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char *argv[])
{
double x, r;
int exp;
x = strtod(argv[1], NULL);
r = frexp(x, &exp);
printf("frexp(%g, &e) = %g: %g * %d^%d = %g\n", x, r, r, 2, exp, x);
exit(EXIT_SUCCESS);
}```