HelenOS sources

isnan             100 uspace/lib/c/include/math.h #define isnan(x)       __builtin_isnan(x)
isnan             122 uspace/lib/c/include/math.h #define isnan(x)       (fpclassify(x) == FP_NAN)
isnan             100 uspace/lib/posix/include/libc/math.h #define isnan(x)       __builtin_isnan(x)
isnan             122 uspace/lib/posix/include/libc/math.h #define isnan(x)       (fpclassify(x) == FP_NAN)