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Diffstat (limited to 'Python/pystrtod.c')
| -rw-r--r-- | Python/pystrtod.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Python/pystrtod.c b/Python/pystrtod.c index 2df4e3d0ad..30dd4e5394 100644 --- a/Python/pystrtod.c +++ b/Python/pystrtod.c @@ -595,6 +595,20 @@ PyOS_ascii_formatd(char *buffer, return buffer; } +/* Precisions used by repr() and str(), respectively. + + The repr() precision (17 significant decimal digits) is the minimal number + that is guaranteed to have enough precision so that if the number is read + back in the exact same binary value is recreated. This is true for IEEE + floating point by design, and also happens to work for all other modern + hardware. + + The str() precision (12 significant decimal digits) is chosen so that in + most cases, the rounding noise created by various operations is suppressed, + while giving plenty of precision for practical use. + +*/ + PyAPI_FUNC(void) _PyOS_double_to_string(char *buf, size_t buf_len, double val, char format_code, int precision, |