TRUNC(3) Library Functions Manual TRUNC(3)

trunc truncf truncl — round to truncated integer value

#include <math.h>

double trunc(double x);
float truncf(float x);
long double truncl(long double x);

The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 (“POSIX.1”) defers to the ISO C standard.

These functions shall round their argument to the integer value, in floating format, nearest to but no larger in magnitude than the argument.

Upon successful completion, these functions shall return the truncated integer value.

If x is NaN, a NaN shall be returned.

If x is ±0 or ±Inf, x shall be returned.

No errors are defined.

None.

None.

None.

None.

The Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <math.h>

First released in Issue 6. Derived from the ISO/IEC 9899:1999 (“ISO C99”) standard.

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December 6, 2001 posix.fail