Provided by: manpages-dev_5.01-1_all #### NAME

```       frexp,  frexpf,  frexpl  -  convert  floating-point  number  to  fractional  and  integral
components

```

#### SYNOPSIS

```       #include <math.h>

double frexp(double x, int *exp);
float frexpf(float x, int *exp);
long double frexpl(long double x, int *exp);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

frexpf(), frexpl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

```

#### DESCRIPTION

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

```

#### RETURNVALUE

```       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.

```

#### ERRORS

```       No errors occur.

```

#### ATTRIBUTES

```       For an explanation of the terms used in this section, see attributes(7).

┌────────────────────────────┬───────────────┬─────────┐
│Interface                   │ Attribute     │ Value   │
├────────────────────────────┼───────────────┼─────────┤
│frexp(), frexpf(), frexpl() │ Thread safety │ MT-Safe │
└────────────────────────────┴───────────────┴─────────┘
```

#### CONFORMINGTO

```       C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

```

#### EXAMPLE

```       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

Program source

#include <math.h>
#include <float.h>
#include <stdio.h>
#include <stdlib.h>

int
main(int argc, char *argv[])
{
double x, r;
int exp;

x = strtod(argv, NULL);
r = frexp(x, &exp);

printf("frexp(%g, &e) = %g: %g * %d^%d = %g\n",
x, r, r, FLT_RADIX, exp, x);
exit(EXIT_SUCCESS);
}

```

#### SEEALSO

```       ldexp(3), modf(3)

```

#### COLOPHON

```       This page is part of release 5.01 of the Linux man-pages project.  A  description  of  the