**diff options**

author | Rich Felker <dalias@aerifal.cx> | 2012-05-05 22:22:46 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2012-05-05 22:22:46 -0400 |

commit | 98c9af500125df41fdb46d7e384b00982d72493a (patch) | |

tree | cb600f99ddc0748c9a579d298f4d6de49f9fb190 /include | |

parent | b4ccc3c1361ca611d6590dd4af288fb9fa6a843b (diff) | |

download | musl-98c9af500125df41fdb46d7e384b00982d72493a.tar.gz |

fix definitions of FP_ILOGB constants

two issues: (1) the type was wrong (unsigned instead of signed int),
and (2) the value of FP_ILOGBNAN should be INT_MIN rather than INT_MAX
to match the ABI. this is also much more useful since INT_MAX
corresponds to a valid input (infinity). the standard would allow us
to set FP_ILOGB0 to -INT_MAX instead of INT_MIN, which would give us
distinct values for ilogb(0) and ilogb(NAN), but the benefit seems way
too small to justify ignoring the ABI.
note that the macro is just a "portable" (to any twos complement
system where signed and unsigned int have the same width) way to write
INT_MIN without needing limits.h. it's valid to use this method since
these macros are not required to work in #if directives.

Diffstat (limited to 'include')

-rw-r--r-- | include/math.h | 4 |

1 files changed, 2 insertions, 2 deletions

diff --git a/include/math.h b/include/math.h index d4359f32..61738e6a 100644 --- a/include/math.h +++ b/include/math.h @@ -28,8 +28,8 @@ extern "C" { #define MATH_ERREXCEPT 2 #define math_errhandling 2 -#define FP_ILOGBNAN (((unsigned)-1)>>1) -#define FP_ILOGB0 (~FP_ILOGBNAN) +#define FP_ILOGBNAN (-1-(int)(((unsigned)-1)>>1)) +#define FP_ILOGB0 FP_ILOGBNAN #define FP_NAN 0 #define FP_INFINITE 1 |