TRUNC(3) | Library Functions Manual | TRUNC(3)

# NAME

`trunc`, `truncf`, `truncl` — nearest integral value with magnitude less than or equal to |x|

# SYNOPSIS

Math Library (libm, -lm)
`#include <math.h>`

double
`trunc`(double x);

float
`truncf`(float x);

long double
`truncl`(long double x);

# DESCRIPTION

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 rounding towards zero mode.

# SEE ALSO

ceil(3), fesetround(3), floor(3), nextafter(3), rint(3), round(3)

# STANDARDS

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

June 7, 2025 | Debian