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%2Flog10.html | 83 +++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 devdocs/c/numeric%2Fmath%2Flog10.html (limited to 'devdocs/c/numeric%2Fmath%2Flog10.html') diff --git a/devdocs/c/numeric%2Fmath%2Flog10.html b/devdocs/c/numeric%2Fmath%2Flog10.html new file mode 100644 index 00000000..5f9bfc00 --- /dev/null +++ b/devdocs/c/numeric%2Fmath%2Flog10.html @@ -0,0 +1,83 @@ +

log10, log10f, log10l

Defined in header <math.h> 
float       log10f( float arg );
+		 (1) (since C99) 
double      log10( double arg );
+		 (2) 
long double log10l( long double arg );
+		 (3) (since C99)
Defined in header <tgmath.h> 
#define log10( arg )
+		 (4) (since C99)
+1-3) Computes the common (base-10) logarithm of arg.
+4) Type-generic macro: If arg has type long double, log10l is called. Otherwise, if arg has integer type or the type double, log10 is called. Otherwise, log10f is called.

Parameters

+ +
arg - floating point value

Return value

If no errors occur, the common (base-10) logarithm of arg (log10(arg) or lg(arg)) is returned.

+

If a domain error occurs, an implementation-defined value is returned (NaN where supported).

+

If a pole error occurs, -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL is returned.

+

Error handling

Errors are reported as specified in math_errhandling.

+

Domain error occurs if arg is less than zero.

+

Pole error may occur if arg is zero.

+

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

+

Example

#include <stdio.h>
+#include <math.h>
+#include <float.h>
+#include <errno.h>
+#include <fenv.h>
+ 
+// #pragma STDC FENV_ACCESS ON
+int main(void)
+{
+    printf("log10(1000) = %f\n", log10(1000));
+    printf("log10(0.001) = %f\n", log10(0.001));
+    printf("base-5 logarithm of 125 = %f\n", log10(125)/log10(5));
+    // special values
+    printf("log10(1) = %f\n", log10(1));
+    printf("log10(+Inf) = %f\n", log10(INFINITY));
+    //error handling
+    errno = 0; feclearexcept(FE_ALL_EXCEPT);
+    printf("log10(0) = %f\n", log10(0));
+    if(errno == ERANGE) perror("    errno == ERANGE");
+    if(fetestexcept(FE_DIVBYZERO)) puts("    FE_DIVBYZERO raised");
+}

Possible output:

+
log10(1000) = 3.000000
+log10(0.001) = -3.000000
+base-5 logarithm of 125 = 3.000000
+log10(1) = 0.000000
+log10(+Inf) = inf
+log10(0) = -inf
+    errno == ERANGE: Numerical result out of range
+    FE_DIVBYZERO raised

References

See also

+ + + +
+
(C99)(C99)
 computes natural (base-e) logarithm (\({\small \ln{x} }\)ln(x))
(function)
+
(C99)(C99)(C99)
 computes base-2 logarithm (\({\small \log_{2}{x} }\)log2(x))
(function)
+
(C99)(C99)(C99)
 computes natural (base-e) logarithm of 1 plus the given number (\({\small \ln{(1+x)} }\)ln(1+x))
(function)
C++ documentation for log10
+

+ © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
+ https://en.cppreference.com/w/c/numeric/math/log10 +

+
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