NAN - cppreference.com

##### cppreference.com

##### Search

Create account

##### Namespaces

- Page
- Discussion

##### Variants

##### Views

- View
- Edit
- History

##### Actions

# NAN

From cppreference.com
< c‎ | numeric‎ | math

Defined in header `<math.h>` |  |
#define NAN /*implementation defined*/ |  | (since C99)

The macro `NAN` expands to constant expression of type float which evaluates to a quiet not-a-number (QNaN) value. If the implementation does not support QNaNs, this macro constant is not defined.

### [edit] Notes

There are many different NaN values, differentiated by their payloads and their sign bits. The contents of the payload and the sign bit of the NaN generated by the macro `NAN` are implementation-defined.

### [edit] References

- C11 standard (ISO/IEC 9899:2011):

  - 7.12/5 NAN (p: 232)

  - F.10/11/13 NAN (p: 518)

- C99 standard (ISO/IEC 9899:1999):

  - 7.12/5 NAN (p: 213)

  - F.9/11/13 NAN (p: 455)

### [edit] See also

nannanfnanl (C99)(C99)(C99) | returns a NaN (not-a-number) (function) [edit]
isnan (C99) | checks if the given number is NaN (function) [edit]
C++ documentation for NAN

Retrieved from "http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/NAN&oldid=77385"