FLOOR(3) Library Functions Manual FLOOR(3)

floor floorf floorl — floor function

#include <math.h>

double floor(double x);
float floorf(float x);
long double floorl(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 POSIX.1-2008 defers to the ISO C standard.

These functions shall compute the largest integral value not greater than x.

[MX] The result shall have the same sign as x.

Upon successful completion, these functions shall return the largest integral value not greater than x, expressed as a , , or , as appropriate for the return type of the function.

[MX] If x is NaN, a NaN shall be returned.

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

No errors are defined.

None.

The integral value returned by these functions might not be expressible as an . The return value should be tested before assigning it to an integer type to avoid the undefined results of an integer overflow.

These functions may raise the inexact floating-point exception if the result differs in value from the argument.

None.

None.

ceil(3), feclearexcept(3), fetestexcept(3), isnan(3)

V1_chap04(7), <math.h>

First released in Issue 1. Derived from Issue 1 of the SVID.

The DESCRIPTION is updated to indicate how an application should check for an error. This text was previously published in the APPLICATION USAGE section.

The () and () functions are added for alignment with the ISO/IEC 9899:1999 (“ISO C99”) standard.

The DESCRIPTION, RETURN VALUE, ERRORS, and APPLICATION USAGE sections are revised to align with the ISO/IEC 9899:1999 (“ISO C99”) standard.

IEC 60559:1989 standard floating-point extensions over the ISO/IEC 9899:1999 (“ISO C99”) standard are marked.

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0141 [346] is applied.

January 1, 2013 posix.fail