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#include <complex.h>
#include <tgmath.h>
 
void func(void) {
  double complex c = 2.0 + 4.0 * I;
  double complex result = log2(c);
}

Compliant Solution

If the programmer's intent was to only take the logarithm of the real part of the complex number. This compliant solution ensures that the logarithm is applied only to the real part of the complex number:

#include <complex.h>
#include <tgmath.h>
 
void func(void) {
  double complex c = 2.0 + 4.0 * I;
  double complex result = log2(real(c));
}

Compliant Solution

If the programmer was intending to take the logarithm of the complex number this compliant solution uses log instead of log2 as log can be used on complex arguments:

#include <complex.h>
#include <tgmath.h>
 
void func(void) {
  double complex c = 2.0 + 4.0 * I;
  double complex result = log(c)/log(2);
}

Noncompliant Code Example

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#include <stdio.h>
#include <string.h>

char *(*fp)(const char *, int);
int main(void) {
  const char *c;
  fp = strchr;
  c = fp('e', "Hello");
  printf("%s\n", c);
  return 0;
}

Compliant Solution

In this compliant solution, the function pointer fp is invoked with the correct number and type of arguments:

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/* In another source file */
long f(long x) {
  return x < 0 ? -x : x;
}

/* In this source file, no f prototype in scope */
long f();
 
long g(int x) {
  return f(x);
}

Compliant Solution

In this compliant solution, the prototype for the function f() is included in the source file in the scope of where it is called, and the function f() is correctly called with an argument of type long:

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