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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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modf(3) Library Functions Manual modf(3)
modf, modff, modfl - extract signed integral and fractional values
from floating-point number
Math library (libm, -lm)
#include <math.h>
double modf(double x, double *iptr);
float modff(float x, float *iptr);
long double modfl(long double x, long double *iptr);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
modff(), modfl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions break the argument x into an integral part and a
fractional part, each of which has the same sign as x. The
integral part is stored in the ___location pointed to by iptr.
These functions return the fractional part of x.
If x is a NaN, a NaN is returned, and *iptr is set to a NaN.
If x is positive infinity (negative infinity), +0 (-0) is
returned, and *iptr is set to positive infinity (negative
infinity).
No errors occur.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│ modf(), modff(), modfl() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
C99, POSIX.1-2001.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
frexp(3), ldexp(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.10.tar.gz
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2025-02-02. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
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[email protected]
Linux man-pages 6.10 2024-07-23 modf(3)
Pages that refer to this page: frexp(3), ldexp(3)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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