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.TH FREXP 2
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.SH NAME
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frexp, ldexp, modf \- split into mantissa and exponent
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.PP
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.B
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double frexp(double value, int *eptr)
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.PP
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.B
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double ldexp(double value, int exp)
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.PP
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.B
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double modf(double value, double *iptr)
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.SH DESCRIPTION
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.I Frexp
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returns the mantissa of
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.I value
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and stores the exponent indirectly through
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.IR eptr ,
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so that
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.I value
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=
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.if t .IR frexp ( value )×2\u\s-2 (*eptr) \s0\d
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.if n .IR frexp ( value )*2** (*eptr).
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.PP
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.I Ldexp
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returns the quantity
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.if t .IR value ×2\u\s-2 exp \s0\d.
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.if n .IR value *2** exp.
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.PP
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.I Modf
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returns the signed fractional part of
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.I value
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and stores the integer part indirectly
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through
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.IR iptr .
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.SH SOURCE
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.B /sys/src/libc/port/frexp.c
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.SH SEE ALSO
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.IR intro (2)
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.SH DIAGNOSTICS
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.I Ldexp
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returns 0 for underflow and the appropriately signed infinity
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for overflow.