isnormal - test for a normal value
int isnormal(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.1-2017 defers to the ISO C standard.
The isnormal() macro shall determine whether its argument value is normal (neither zero, subnormal, infinite, nor NaN). First, an argument represented in a format wider than its semantic type is converted to its semantic type. Then determination is based on the type of the argument.
The isnormal() macro shall return a non-zero value if and only if its argument has a normal value.
No errors are defined.
fpclassify, isfinite, isinf, isnan, signbit
First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.
return to top of page