To get a trial key
fill out the form below
Team license
Enterprise license
** By clicking this button you agree to our Privacy Policy statement

Request our prices
New License
License Renewal
--Select currency--
USD
EUR
RUB
* By clicking this button you agree to our Privacy Policy statement

Free PVS-Studio license for Microsoft MVP specialists
** By clicking this button you agree to our Privacy Policy statement

To get the licence for your open-source project, please fill out this form
** By clicking this button you agree to our Privacy Policy statement

I am interested to try it on the platforms:
** By clicking this button you agree to our Privacy Policy statement

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.

>
>
>
V2604. MISRA. Features from <stdarg.…
Analyzer diagnostics
General Analysis (C++)
General Analysis (C#)
General Analysis (Java)
Diagnosis of micro-optimizations (C++)
Diagnosis of 64-bit errors (Viva64, C++)
Customer specific requests (C++)
MISRA errors
AUTOSAR errors
OWASP errors (C#)
Problems related to code analyzer
Additional information
Contents

V2604. MISRA. Features from <stdarg.h> should not be used.

Jul 26 2021

This diagnostic rule is based on the MISRA (Motor Industry Software Reliability Association) manual for software development.

This rule only applies to C.

You shouldn't use the '<stdarg.h>' header file that includes the 'va_list' type , as well as macros 'va_arg', 'va_start', ' va_end' and 'va_copy'. They are necessary for working with functions with a variable number of arguments. However, the improper use of the '<stdarg.h>' header file often causes undefined behavior.

Look at the example:

#include <stdint.h>
#include <stdarg.h>

void foo(va_list args)
{
  double y;
  y = va_arg(args, int);
}

void bar(uint16_t count, ...)
{
  uint16_t x;
  va_list ap;
  va_start (ap, count); // <=
  x = va_arg (ap, int);
  foo(ap);
  x = va_arg (ap, int);
}

void baz(void)
{
  bar(1.25, 10.07);
}

The code above demonstrates several problems that can lead to undefined behavior. Note: the list below contains only the issues that relate to this diagnostic:

  • The 'va_start' macro is called in the 'bar' function. However, the 'va_end' macro is not called.
  • The 'va_arg' macro is applied to the same 'va_list' object in different functions. The developer cannot control the what state the argument list is in as well as the number of elements that were extracted from it after passing the 'ap' variable to the function. Hence the problem.
  • The 'bar' function with the arguments of the 'double' type is called in the 'baz' function, although the 'bar' function expects 'int'. Calling the 'bar' function can lead to data loss.

This diagnostic is classified as:

  • MISRA-C-17.1
Unicorn with delicious cookie
Our website uses cookies to enhance your browsing experience.
Accept