From 754bbf7a25a8dda49b5d08ef0d0443bbf5af0e36 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 7 Apr 2024 13:41:34 -0500 Subject: new repository --- devdocs/c/numeric%2Fmath%2Ffpclassify.html | 52 ++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 devdocs/c/numeric%2Fmath%2Ffpclassify.html (limited to 'devdocs/c/numeric%2Fmath%2Ffpclassify.html') diff --git a/devdocs/c/numeric%2Fmath%2Ffpclassify.html b/devdocs/c/numeric%2Fmath%2Ffpclassify.html new file mode 100644 index 00000000..0014938b --- /dev/null +++ b/devdocs/c/numeric%2Fmath%2Ffpclassify.html @@ -0,0 +1,52 @@ +

fpclassify

Defined in header <math.h> 
#define fpclassify(arg) /* implementation defined */
+		 (since C99)

Categorizes floating point value arg into the following categories: zero, subnormal, normal, infinite, NAN, or implementation-defined category. The macro returns an integral value.

+

FLT_EVAL_METHOD is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that: a normal long double value might become subnormal when converted to double and zero when converted to float.

+

Parameters

+ +
arg - floating point value

Return value

One of FP_INFINITE, FP_NAN, FP_NORMAL, FP_SUBNORMAL, FP_ZERO or implementation-defined type, specifying the category of arg.

+

Example

#include <stdio.h>
+#include <math.h>
+#include <float.h>
+ 
+const char *show_classification(double x) {
+    switch(fpclassify(x)) {
+        case FP_INFINITE:  return "Inf";
+        case FP_NAN:       return "NaN";
+        case FP_NORMAL:    return "normal";
+        case FP_SUBNORMAL: return "subnormal";
+        case FP_ZERO:      return "zero";
+        default:           return "unknown";
+    }
+}
+int main(void)
+{
+    printf("1.0/0.0 is %s\n", show_classification(1/0.0));
+    printf("0.0/0.0 is %s\n", show_classification(0.0/0.0));
+    printf("DBL_MIN/2 is %s\n", show_classification(DBL_MIN/2));
+    printf("-0.0 is %s\n", show_classification(-0.0));
+    printf("1.0 is %s\n", show_classification(1.0));
+}

Output:

+
1.0/0.0 is Inf
+0.0/0.0 is NaN
+DBL_MIN/2 is subnormal
+-0.0 is zero
+1.0 is normal

References

See also

+ + + + +
+
(C99)
 checks if the given number has finite value
(function macro)
+
(C99)
 checks if the given number is infinite
(function macro)
+
(C99)
 checks if the given number is NaN
(function macro)
+
(C99)
 checks if the given number is normal
(function macro)
C++ documentation for fpclassify
+

+ © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
+ https://en.cppreference.com/w/c/numeric/math/fpclassify +

+
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