Should main return 0 when there is a while(1) ?

[Remi99]

Hi all,

I'm programming an embedded software.

According to C standards, I write : 

 

 

int main(void)
{
 // Init
 initMethod();

 /* Main loop */
 while (1)
 {
 execute();
 }

 // This return is never reached
 return 0;
}

 

 

But when my code is analyzed by SonarQube, I have a bug report: 'return' will never be executed.

To fix it, I would write the following:

 

 

int main(void)
{
 // Init
 initMethod();

 /* Main loop */
 while (1)
 {
 execute();
 }
}

 

 

But I'm annoyed with the fact that the main method doesn't have the "good" return type.
What is the good pratice in this case ?

Best regards.

[q3z85d41xqz036d]

In C, the return statement should always match the return type. What you did is good and that warning is not so important. I dont know where it come from, because its not a warning-case of gcc. Maybe it come from another parser.

[q3z85d41xqz036d]

Or maybe its come from gcc with compilation flags ?

Do you know how your project is compiled ?

[Remi99]

For more information, here is the SonarQube rules : 

 

 

[mƎALLEm]

Hello,

Indeed in your case the return will never reached because of the while(1) loop. But, normally, it should be treated as a warning not an error.

[q3z85d41xqz036d]

is gcc is your compiler ?

[q3z85d41xqz036d]

There are severals "norms" about compiling C code around the world and epoch.
Yours seems to unaccept unreachable code. This is just a detail.
Later in your project, you will probably add some conditions to exit this while loop, and so you will have to add a return statement in your function.

[Remi99]

I'm talking about quality. Not about compilation error. 
The program compiles well and runs. But SonarQube (quality tool) return that the first code is not well written.

[q3z85d41xqz036d]

Here, its not about code quality, but about follow the norms of your compiler.

[Pavel A.]

Since C99, int main() does NOT have to return anything. Now you can understand why they made this improvement ))

[Tesla DeLorean]

The bigger question is WHERE it would return too? Not even sure the GNU startup would get you to exit()

Can you define it as not returning a value, and likely never leaving?

[Pavel A.]

> Not even sure the GNU startup would get you to exit()

At least there's the return instruction. In standalone environment aka "bare metal"  exit() is not warranted.

https://github.com/STMicroelectronics/cmsis_device_f4/blob/2e1724e592931693ce4dfc43e2fd6b3bc375d6a0/Source/Templates/gcc/startup_stm32f401xc.s#L101

 

[Pavel A.]

> But I'm annoyed with the fact that the main method doesn't have the "good" return type.

Int is the perfect return type for main(). The good practice? Before taking on a project, verify which language version and coding guidelines should be used. Refresh your C. Read documentation. Repeat every so often.