signbit - test sign
int signbit(real-floating x);
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard.
The signbit() macro shall determine whether the sign of its argument value is negative. NaNs, zeros, and infinities have a sign bit.
The signbit() macro shall return a non-zero value if and only if the sign of its argument value is negative.
No errors are defined.
fpclassify , isfinite , isinf , isnan , isnormal
First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.
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