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+--- Forum: MISRA-C: 2004 rules (https://forum.misra.org.uk/forumdisplay.php?fid=17)
+---- Forum: 6.9 Initialisation (https://forum.misra.org.uk/forumdisplay.php?fid=36)
+---- Thread: 9.1 Variable may not have been initialized (/showthread.php?tid=1400)
9.1 Variable may not have been initialized - ankitshah413 - 19-02-2018
Hello,
I have an issue with MISRA 9.1 rule. In my code i have a "if" loop and inside that a variable is initialized and then is read after that. But when i do static analysis using pclint then i have a warning for 9.1 rule. Below is my code :
struct mgm2_info_return msg_ascu_info;
Code:
if(klr_ecuConf_t->feat_multislave)
{
msg_ascu_info = mgmF_massage_get_ascu_info();
}
msg_info = mgmF_massage_get_info();The line where it is read and where warning occurs:
Code:
if( (((vF_mcms_fl_on((tm_uint8)V_FLONCMD_ACK)) ||
(msg_info.pmcu_state == LDF_MASSSQC_STATE_ACTIVE))
&&((klr_ecuConf_t->feat_multislave)
|| (msg_ascu_info.ascu_state == LDF_MASSSQC_STATE_ACTIVE))
) &&
(msg_info.pmcu_trig_source == RqSource_ActvComf))Do i need to write a justification or i need to initialize the entire structure first?
Re: 9.1 Variable may not have been initialized - dg1980 - 20-02-2018
Be advised that MISRA 2004 is superseded by MISRA 2012 and that rule 9.1 has become mandatory - no deviation permitted.
If msg_ascu_info is a stack variable and the two if statements shown are sequential you have a serious problem if klr_ecuConf_t->feat_multislave is zero.
Re: 9.1 Variable may not have been initialized - ankitshah413 - 20-02-2018
Yes, the two IF statements are sequential. But here klr_ecuConf_t->feat_multislave is assigned a value that is greater then zero at runtime as it is a slave variant.
But, it is not assigned any value in this function.
Re: 9.1 Variable may not have been initialized - misra-c - 27-04-2018
This code will be a violation of rule 9.1 if it can be shown that this code can be reached when "klr_ecuConf_t->feat_multislave" is False and "msg_ascu_info" is unset. Without the full code it is not possible to give a definite answer.
If the code is very complex, it may not be possible for a static analysis to determine whether the above conditions are met or not.
Re: 9.1 Variable may not have been initialized - Francois - 30-04-2018
You may have to write your code differently and less complex.
1. The first IF doesn't perform a real test. Actually you're only test that the variable is not empty, instead of "== true/false/on/off/etc .
2. For the second IF, you know that the compiler will generate/use temporary variables/registers to store temporary test results.
My opinion is: Do it yourself :). Create local variables to store your checks.
Small tasks are easier to read/maintain/debug/optimize ^^
One example:
Code:
..(vF_mcms_fl_on((tm_uint8)V_FLONCMD_ACK)) || (msg_info.pmcu_state == LDF_MASSSQC_STATE_ACTIVE)...You're comparing return of a function with the result of a test.
i assume that the result of the function, even if you define a boolean type, is not the same type of the "==" test result...