TRUNC(3) Library Functions Manual TRUNC(3)

trunctruncate to integer value

#include <math.h>

double
trunc(double x);

long double
truncl(long double x);

float
truncf(float x);

The () functions return the integral value nearest to but no larger in magnitude than x.

trunc(±0) returns ±0.

(±infinity) returns ±infinity.

If you need to apply the trunc() function to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may give significantly better performance:

#include <Accelerate/Accelerate.h>

vFloat (vFloat x);
void (float *y, const float *x, const int *n);
void (double *y, const double *x, const int *n);

ceil(3), floor(3), round(3), math(3)

The trunc() functions conform to ISO/IEC 9899:2011.

December 11, 2006 macOS 15.2