| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
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| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
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| .\" Formatted or processed versions of this manual, if unaccompanied by |
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| .\" %%%LICENSE_END |
| .\" |
| .\" References consulted: |
| .\" Linux libc source code |
| .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) |
| .\" 386BSD man pages |
| .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) |
| .\" Modified 2002-07-27 by Walter Harms |
| .\" (walter.harms@informatik.uni-oldenburg.de) |
| .\" |
| .TH MODF 3 2017-09-15 "" "Linux Programmer's Manual" |
| .SH NAME |
| modf, modff, modfl \- extract signed integral and fractional values from |
| floating-point number |
| .SH SYNOPSIS |
| .nf |
| .B #include <math.h> |
| .PP |
| .BI "double modf(double " x ", double *" iptr ); |
| .BI "float modff(float " x ", float *" iptr ); |
| .BI "long double modfl(long double " x ", long double *" iptr ); |
| .fi |
| .PP |
| Link with \fI\-lm\fP. |
| .PP |
| .in -4n |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .in |
| .PP |
| .ad l |
| .BR modf (), |
| .BR modfl (): |
| .RS 4 |
| _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
| || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .RE |
| .ad |
| .SH DESCRIPTION |
| These functions break the argument |
| .I x |
| into an integral |
| part and a fractional part, each of which has the same sign as |
| .IR x . |
| The integral part is stored in the location pointed to by |
| .IR iptr . |
| .SH RETURN VALUE |
| These functions return the fractional part of |
| .IR x . |
| .PP |
| If |
| .I x |
| is a NaN, a NaN is returned, and |
| .IR *iptr |
| is set to a NaN. |
| .PP |
| If |
| .I x |
| is positive infinity (negative infinity), +0 (\-0) is returned, and |
| .IR *iptr |
| is set to positive infinity (negative infinity). |
| .SH ERRORS |
| No errors occur. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lbw24 lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR modf (), |
| .BR modff (), |
| .BR modfl () |
| T} Thread safety MT-Safe |
| .TE |
| .SH CONFORMING TO |
| C99, POSIX.1-2001, POSIX.1-2008. |
| .PP |
| The variant returning |
| .I double |
| also conforms to |
| SVr4, 4.3BSD, C89. |
| .SH SEE ALSO |
| .BR frexp (3), |
| .BR ldexp (3) |
