osx man page for trunc

TRUNC(3)						   BSD Library Functions Manual 						  TRUNC(3)

NAME
     trunc -- truncate to integer value

SYNOPSIS
     #include <math.h>

     double
     trunc(double x);

     long double
     truncl(long double x);

     float
     truncf(float x);

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

SPECIAL VALUES
     trunc(+-0) returns +-0.

     trunc(+-infinity) returns +-infinity.

VECTOR OPERATIONS
     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 vintf(vFloat x);
     void vvintf(float *y, const float *x, const int *n);
     void vvint(double *y, const double *x, const int *n);

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

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

BSD
								 December 11, 2006							       BSD