1 #include <fenv.h>
2 #include <limits.h>
3 #include <math.h>
4 #include <stdint.h>
5 #include <stdio.h>
6 
DivideByZero()7 static void DivideByZero() {
8   // volatile to prevent compiler optimizations.
9   volatile float zero = 0.0f;
10   volatile float result __attribute__((unused)) = 123.0f / zero;
11 }
12 
main()13 int main () {
14    /* Testing lrint. */
15    fesetround(FE_UPWARD); // lrint/lrintf/lrintl obey the rounding mode.
16    printf("fesetround(FE_UPWARD)\n");
17    printf("lrint(1234.01): %ld\n", lrint(1234.01));
18    printf("lrintf(1234.01f): %ld\n", lrintf(1234.01f));
19    printf("lrintl(1234.01): %ld\n", lrintl(1234.01));
20    fesetround(FE_TOWARDZERO); // lrint/lrintf/lrintl obey the rounding mode.
21    printf("fesetround(FE_TOWARDZERO)\n");
22    printf("lrint(1234.01): %ld\n", lrint(1234.01));
23    printf("lrintf(1234.01f): %ld\n", lrintf(1234.01f));
24    printf("lrintl(1234.01): %ld\n", lrintl(1234.01));
25    fesetround(FE_UPWARD); // llrint/llrintf/llrintl obey the rounding mode.
26    printf("fesetround(FE_UPWARD)\n");
27    printf("llrint(1234.01): %lld\n", llrint(1234.01));
28    printf("llrintf(1234.01f): %lld\n", llrintf(1234.01f));
29    printf("llrintf(1234.01f): %lld\n", llrintl(1234.01));
30    fesetround(FE_TOWARDZERO); // llrint/llrintf/llrintl obey the rounding mode.
31    printf("fesetround(FE_TOWARDZERO)\n");
32    printf("llrint(1234.01): %lld\n", llrint(1234.01));
33    printf("llrintf(1234.01f): %lld\n", llrintf(1234.01f));
34    printf("llrintl(1234.01): %lld\n", llrintl(1234.01));
35 
36    /* Tesing rint. */
37    fesetround(FE_UPWARD); // rint/rintf/rintl obey the rounding mode.
38    printf("fesetround(FE_UPWARD)\n");
39    feclearexcept(FE_ALL_EXCEPT); // rint/rintf/rintl do set the FE_INEXACT flag.
40    printf("feclearexcept(FE_ALL_EXCEPT)\n");
41    printf("rint(1234.0): %f\n", rint(1234.0));
42    printf("(fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT): %d\n",
43            (fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT));
44    printf("rint(1234.01): %f\n", rint(1234.01));
45    printf("(fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT): %d\n",
46            (fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT));
47 
48    feclearexcept(FE_ALL_EXCEPT); // rint/rintf/rintl do set the FE_INEXACT flag.
49    printf("feclearexcept(FE_ALL_EXCEPT)\n");
50    printf("rintf(1234.0f): %f\n", rintf(1234.0f));
51    printf("(fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT): %d\n",
52            (fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT));
53    printf("rintf(1234.01f): %f\n", rintf(1234.01f));
54    printf("(fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT): %d\n",
55            (fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT));
56 
57    feclearexcept(FE_ALL_EXCEPT); // rint/rintf/rintl do set the FE_INEXACT flag.
58    printf("feclearexcept(FE_ALL_EXCEPT)\n");
59    printf("rintl(1234.0): %Lf\n", rintl(1234.0));
60    printf("(fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT): %d\n",
61            (fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT));
62    printf("rintl(1234.01): %Lf\n", rintl(1234.01));
63    printf("(fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT): %d\n",
64            (fetestexcept(FE_ALL_EXCEPT) & FE_INEXACT));
65 
66    fesetround(FE_TOWARDZERO); // rint/rintf obey the rounding mode.
67    printf("fesetround(FE_TOWARDZERO)\n");
68    printf("rint(1234.01): %f\n", rint(1234.01));
69    printf("rintf(1234.01f): %f\n", rintf(1234.01f));
70    printf("rintl(1234.01): %Lf\n", rintl(1234.01));
71 
72    /* Testing nearbyint. */
73    fesetround(FE_UPWARD); // nearbyint/nearbyintf/nearbyintl obey the rounding mode.
74    printf("fesetround(FE_UPWARD)\n");
75    feclearexcept(FE_ALL_EXCEPT); // nearbyint/nearbyintf/nearbyintl don't set the FE_INEXACT flag.
76    printf("feclearexcept(FE_ALL_EXCEPT)\n");
77    printf("nearbyint(1234.0): %f\n", nearbyint(1234.0));
78    printf("nearbyint(1234.01): %f\n", nearbyint(1234.01));
79 
80    feclearexcept(FE_ALL_EXCEPT);
81    printf("feclearexcept(FE_ALL_EXCEPT)\n");
82    printf("nearbyintf(1234.0f): %f\n", nearbyintf(1234.0f));
83    printf("nearbyintf(1234.01f): %f\n", nearbyintf(1234.01f));
84 
85    feclearexcept(FE_ALL_EXCEPT); // nearbyint/nearbyintf/nearbyintl don't set the FE_INEXACT flag.
86    printf("feclearexcept(FE_ALL_EXCEPT)\n");
87    printf("nearbyintl(1234.0f): %Lf\n", nearbyintl(1234.0f));
88    printf("nearbyintl(1234.01f): %Lf\n", nearbyintl(1234.01f));
89 
90    fesetround(FE_TOWARDZERO); // nearbyint/nearbyintf/nearbyintl obey the rounding mode.
91    printf("fesetround(FE_TOWARDZERO)\n");
92    printf("nearbyint(1234.01): %f\n", nearbyint(1234.01));
93    printf("nearbyintf(1234.01f): %f\n", nearbyintf(1234.01f));
94    printf("nearbyintl(1234.01): %Lf\n", nearbyintl(1234.01));
95 
96    /* Test log. */
97    printf("log(M_E): %lf\n", log(M_E));
98 
99    /* Test tgamma. */
100    printf("tgamma(5.0): %lf\n", tgamma(5.0));
101 
102    /* Test cbrt. */
103    printf("cbrt(27.0): %lf\n", cbrt(27.0));
104 
105    /* Test dividing by zero. */
106    // Clearing clears.
107    printf("feclearexcept(FE_ALL_EXCEPT): %d\n", feclearexcept(FE_ALL_EXCEPT));
108 
109    // Dividing by zero sets FE_DIVBYZERO.
110    DivideByZero();
111    int raised = fetestexcept(FE_DIVBYZERO | FE_OVERFLOW);
112    printf("raised: %d\n", raised);
113 
114    return 0;
115 }
116