trunc(3)

trunc3

Nearest integral value with magnitude less than or equal to |x|

Usage

#include <math.h>

double

trunc(double x);

float

truncf(float x);

long double

truncl(long double x);

Library

Math Library (libm, -lm)

Overview

The trunc(), truncf(), and truncl() functions return the nearest integral value with magnitude less than or equal to |x|. They are equivalent to rint(), rintf(), and rintl(), respectively, in the FE_TOWARDZERO rounding mode.

Releases

52 releases since FreeBSD 5.3-RELEASE; the text changed 33 times.

  1. 5.3–5.5
  2. 6.0–6.3
  3. 6.4
  4. 7.0
  5. 7.1
  6. 7.2
  7. 7.3
  8. 7.4
  9. 8.0
  10. 8.1
  11. 8.2
  12. 8.3
  13. 8.4
  14. 9.0
  15. 9.1
  16. 9.2
  17. 9.3
  18. 10.0
  19. 10.1
  20. 10.2
  21. 10.3
  22. 10.4
  23. 11.0
  24. 11.1
  25. 11.2
  26. 11.3
  27. 11.4
  28. 12.0
  29. 12.1
  30. 12.2
  31. 12.3
  32. 12.4
  33. 13.0–13.2
  34. 13.3–16.0

Standards

The trunc(), truncf(), and truncl() functions conform to ISO/IEC 9899:1999 (“ISO C99”).

History

These routines first appeared in FreeBSD 5.3.

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