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      signbit

      From cppreference.com
      <c‎ |numeric‎ |math
       
       
       
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      Defined in header<math.h>
      #define signbit( arg ) /* implementation defined */
      (since C99)

      Determines if the given floating-point numberarg is negative. The macro returns an integral value.

      Contents

      [edit]Parameters

      arg - floating-point value

      [edit]Return value

      Nonzero integral value ifarg is negative,0 otherwise.

      [edit]Notes

      This macro detects the sign bit of zeroes, infinities, and NaNs. Along withcopysign, this macro is one of the only two portable ways to examine the sign of a NaN.

      [edit]Example

      Run this code
      #include <math.h>#include <stdio.h> int main(void){printf("signbit(+0.0) = %d\n", signbit(+0.0));printf("signbit(-0.0) = %d\n", signbit(-0.0));}

      Possible output:

      signbit(+0.0) = 0signbit(-0.0) = 128

      [edit]References

      • C23 standard (ISO/IEC 9899:2024):
      • 7.12.3.6 The signbit macro (p: TBD)
      • C17 standard (ISO/IEC 9899:2018):
      • 7.12.3.6 The signbit macro (p: TBD)
      • C11 standard (ISO/IEC 9899:2011):
      • 7.12.3.6 The signbit macro (p: 237)
      • C99 standard (ISO/IEC 9899:1999):
      • 7.12.3.6 The signbit macro (p: 218)

      [edit]See also

      (C99)(C99)
      computes absolute value of a floating-point value (\(\small{|x|}\)|x|)
      (function)[edit]
      produces a value with the magnitude of a given value and the sign of another given value
      (function)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=c/numeric/math/signbit&oldid=172062"

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