/C

# floor, floorf, floorl

Defined in header `<math.h>`
`float       floorf( float arg );`
(1) (since C99)
`double      floor( double arg );`
(2)
`long double floorl( long double arg );`
(3) (since C99)
Defined in header `<tgmath.h>`
`#define floor( arg )`
(4) (since C99)
1-3) Computes the largest integer value not greater than `arg`.
4) Type-generic macro: If `arg` has type `long double`, `floorl` is called. Otherwise, if `arg` has integer type or the type `double`, `floor` is called. Otherwise, `floorf` is called.

### Parameters

 arg - floating point value

### Return value

If no errors occur, the largest integer value not greater than `arg`, that is ⌊arg⌋, is returned.

Return value
Argument

### Error handling

Errors are reported as specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

• The current rounding mode has no effect.
• If `arg` is ±∞, it is returned, unmodified
• If `arg` is ±0, it is returned, unmodified
• If arg is NaN, NaN is returned

### Notes

`FE_INEXACT` may be (but isn't required to be) raised when rounding a non-integer finite value.

The largest representable floating-point values are exact integers in all standard floating-point formats, so this function never overflows on its own; however the result may overflow any integer type (including `intmax_t`), when stored in an integer variable.

### Example

```#include <math.h>
#include <stdio.h>
int main(void)
{
printf("floor(+2.7) = %+.1f\n", floor(2.7));
printf("floor(-2.7) = %+.1f\n", floor(-2.7));
printf("floor(-0.0) = %+.1f\n", floor(-0.0));
printf("floor(-Inf) = %+f\n",   floor(-INFINITY));
}```

Possible output:

```floor(+2.7) = +2.0
floor(-2.7) = -3.0
floor(-0.0) = -0.0
floor(-Inf) = -inf```

### References

• C11 standard (ISO/IEC 9899:2011):
• 7.12.9.2 The floor functions (p: 251)
• 7.25 Type-generic math <tgmath.h> (p: 373-375)
• F.10.6.2 The floor functions (p: 526)
• C99 standard (ISO/IEC 9899:1999):
• 7.12.9.2 The floor functions (p: 232)
• 7.22 Type-generic math <tgmath.h> (p: 335-337)
• F.9.6.2 The floor functions (p: 463)
• C89/C90 standard (ISO/IEC 9899:1990):
• 4.5.6.3 The floor function