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Diffstat (limited to 'manual/arith.texi')
| -rw-r--r-- | manual/arith.texi | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/manual/arith.texi b/manual/arith.texi index 58f35781bb..a13c46f0ec 100644 --- a/manual/arith.texi +++ b/manual/arith.texi @@ -361,6 +361,23 @@ You should therefore use the specific macros whenever possible. @comment math.h @comment ISO +@deftypefn {Macro} int iscanonical (@emph{float-type} @var{x}) +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} +In some floating-point formats, some values have canonical (preferred) +and noncanonical encodings (for IEEE interchange binary formats, all +encodings are canonical). This macro returns a nonzero value if +@var{x} has a canonical encoding. It is from TS 18661-1:2014. + +Note that some formats have multiple encodings of a value which are +all equally canonical; @code{iscanonical} returns a nonzero value for +all such encodings. Also, formats may have encodings that do not +correspond to any valid value of the type. In ISO C terms these are +@dfn{trap representations}; in @theglibc{}, @code{iscanonical} returns +zero for such encodings. +@end deftypefn + +@comment math.h +@comment ISO @deftypefn {Macro} int isfinite (@emph{float-type} @var{x}) @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} This macro returns a nonzero value if @var{x} is finite: not plus or |