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V621. Loop may execute incorrectly...
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V621. Loop may execute incorrectly or may not execute at all. Consider inspecting the 'for' operator.

03 Jul 2012

The analyzer has detected a potential error: odd initial and finite counter values are used in the 'for' operator. It may cause incorrect loop execution and break the program execution logic.

Consider the following example:

signed char i;
for (i = -10; i < 100; i--)
{
  ...
};

Perhaps there is a misprint here causing the initial and finite values to be mixed up. The error may also occur if operators '++' and '--' are mixed up.

This is the correct code:

for (i = -10; i < 100; i++)
{
  ...
};

The following code is also correct:

for (i = 100; i > -10; i--)
{
...
};

Consider the following code sample found by the analyzer in a real application:

void CertificateRequest::Build()
{
    ...
    uint16 authCount = 0;

    for (int j = 0; j < authCount; j++) {
      int sz = REQUEST_HEADER + MIN_DIS_SIZE;
      ...
    }
}

The 'authCount' variable is initialized by an incorrect value or perhaps there is even some other variable to be used here.

This diagnostic is classified as:

You can look at examples of errors detected by the V621 diagnostic.