modf(3)

modf3

Extract signed integral and fractional values from floating-point number

Usage

#include <math.h>

double

modf(double value, double *iptr);

float

modff(float value, float *iptr);

long double

modfl(long double value, long double *iptr);

Library

Math Library (libm, -lm)

Overview

The modf(), modff(), and modfl() functions break the argument value into integral and fractional parts, each of which has the same sign as the argument. It stores the integral part as a floating point number in the object pointed to by iptr.

Return values

These functions return the signed fractional part of value.

Releases

87 releases since FreeBSD 2.0.5-RELEASE; the text changed 41 times.

  1. 2.0.5–3.4
  2. 3.5–3.5.1
  3. 4.0
  4. 4.1–4.2
  5. 4.3–4.4
  6. 4.5–4.7
  7. 4.8–4.11
  8. 5.0
  9. 5.1–6.3
  10. 6.4
  11. 7.0
  12. 7.1
  13. 7.2
  14. 7.3
  15. 7.4
  16. 8.0
  17. 8.1
  18. 8.2
  19. 8.3
  20. 8.4
  21. 9.0
  22. 9.1
  23. 9.2
  24. 9.3
  25. 10.0
  26. 10.1
  27. 10.2
  28. 10.3
  29. 10.4
  30. 11.0
  31. 11.1
  32. 11.2
  33. 11.3
  34. 11.4
  35. 12.0
  36. 12.1
  37. 12.2
  38. 12.3
  39. 12.4
  40. 13.0–13.2
  41. 13.3–14.5
  42. 15.0–16.0

Standards

The modf(), modff(), and modfl() functions conform to ISO/IEC 9899:1999 (“ISO C99”).

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.