| rsc | cfa37a7 | 2004-04-10 18:53:55 +0000 | [diff] [blame] | 1 | .TH NAN 3 |
| 2 | .SH NAME |
| 3 | NaN, Inf, isNaN, isInf \- not-a-number and infinity functions |
| 4 | .SH SYNOPSIS |
| 5 | .B #include <u.h> |
| 6 | .br |
| 7 | .B #include <libc.h> |
| 8 | .PP |
| 9 | .ta \w'\fLdouble 'u |
| 10 | .B |
| 11 | double NaN(void) |
| 12 | .PP |
| 13 | .B |
| 14 | double Inf(int) |
| 15 | .PP |
| 16 | .B |
| 17 | int isNaN(double) |
| 18 | .PP |
| 19 | .B |
| 20 | int isInf(double, int) |
| 21 | .SH DESCRIPTION |
| 22 | The IEEE floating point standard defines values called |
| 23 | `not-a-number' and positive and negative `infinity'. |
| 24 | These values can be produced by such things as overflow |
| 25 | and division by zero. |
| 26 | Also, the library functions sometimes return them when |
| 27 | the arguments are not in the domain, or the result is |
| 28 | out of range. |
| 29 | .PP |
| 30 | .I NaN |
| 31 | returns a double that is not-a-number. |
| 32 | .I IsNaN |
| 33 | returns true if its argument is not-a-number. |
| 34 | .PP |
| 35 | .IR Inf ( i ) |
| 36 | returns positive infinity if |
| 37 | .I i |
| 38 | is greater than or equal to zero, |
| 39 | else negative infinity. |
| 40 | .I IsInf |
| 41 | returns true if its first argument is infinity |
| 42 | with the same sign as the second argument. |
| 43 | .SH SOURCE |
| rsc | c3674de | 2005-01-11 17:37:33 +0000 | [diff] [blame] | 44 | .B \*9/src/lib9/nan.c |
