To get a trial key
fill out the form below
Team License (standard version)
Enterprise License (extended version)
* By clicking this button you agree to our Privacy Policy statement

** This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Request our prices
New License
License Renewal
--Select currency--
USD
EUR
GBP
RUB
* By clicking this button you agree to our Privacy Policy statement

** This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Message submitted.

Your message has been sent. We will email you at


If you haven't received our response, please do the following:
check your Spam/Junk folder and click the "Not Spam" button for our message.
This way, you won't miss messages from our team in the future.

>
>
>
V815. Decreased performance. Consider r…
Analyzer Diagnostics
General Analysis (C++)
General Analysis (C#)
General Analysis (Java)
Diagnosis of micro-optimizations (C++)
Diagnosis of 64-bit errors (Viva64, C++)
MISRA errors
AUTOSAR errors
Additional information
Contents

V815. Decreased performance. Consider replacing the expression 'AA' with 'BB'.

May 16, 2014

The analyzer has detected a construct that can be optimized: in string classes, operators are implemented that allow more efficient string clearing or checking a string for being empty.

For example:

bool f(const std::string &s)
{
  if (s == "")
    return false;
  ....
}

This code can be improved a bit. The object of the 'std::string' class knows the length of the string it is storing, but it is unknown which string it is intended to be compared to. That's why a loop is called for string comparing. A much easier and better way is to simply check that the string length is 0 - it can be done with the help of the 'empty()' function:

if (s.empty())
  return false;

A similar situation: we need to clear a string in the code fragment below, and it can be improved:

wstring str;
...
str = L"";

The better version:

wstring str;
...
str.clear();

Note. The recommendations given are arguable. Such optimizations give little benefit, while the risk is increasing of making a typo and using a wrong function. The reason for that is poor function naming. For example, the 'empty()' function in the 'std::string' class checks the string for being empty. In the class 'CString', the 'Empty()' function clears the string. The same name for both but these functions do different things. That's why you may use the constructs = "", == "", != "" to make the code more comprehensible.

The choice is up to you. If you don't like the V815 diagnostic rule, you can turn it off in the settings.

This website uses cookies and other technology to provide you a more personalized experience. By continuing the view of our web-pages you accept the terms of using these files. If you don't want your personal data to be processed, please, leave this site.
Learn More →
Accept