1#include <float.h>
2#include <math.h>
3
4#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
5long double fmaxl(long double x, long double y) {
6    return fmax(x, y);
7}
8#else
9long double fmaxl(long double x, long double y) {
10    if (isnan(x))
11        return y;
12    if (isnan(y))
13        return x;
14    /* handle signed zeros, see C99 Annex F.9.9.2 */
15    if (signbit(x) != signbit(y))
16        return signbit(x) ? y : x;
17    return x < y ? y : x;
18}
19#endif
20