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[Solved] Disable "May be missing a break" warnings

 
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allenhuffman



Joined: 17 Jun 2019
Posts: 537
Location: Des Moines, Iowa, USA

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[Solved] Disable "May be missing a break" warnings
PostPosted: Fri Jan 31, 2020 2:01 pm     Reply with quote
Code:
>>> Warning 242 "C:\Program Files (x86)\PICC\Drivers\math.h" Line 1799(10,11): May be missing a break


On some compilers, there is an extension to tell the compiler it's okay to do things like this:

Code:
switch (i)
{
   case 1:
   case 2:
      break;

   case 4:
      // do something
   case 5:
      // then do this
      break;

   default:
      break;
}


CCS has warnings in the math.h file, and under GCC and other compilers you can add a special comment or keyword to tell the compiler it's intentional.

Code:

case 1: // Depending on GCC version, one of these used to work:
   //fall through
   //no break
case 2:
   // stuff
   break;


In an effort to clean up some of our code, I want to eliminate compiler warnings, but since I get some in the CCS-provided header files, I'm not sure what to do there.
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?

Last edited by allenhuffman on Tue Feb 04, 2020 8:36 am; edited 4 times in total
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Jan 31, 2020 2:20 pm     Reply with quote
Quote:
#ignore_warnings

Syntax:
#ignore_warnings ALL
#IGNORE_WARNINGS NONE
#IGNORE_WARNINGS warnings

Elements:
warnings is one or more warning numbers separated by commas.

Description:
This function will suppress warning messages from the compiler.

ALL indicates no warnings will be generated.

NONE indicates all warnings will be generated. If numbers are listed then
those warnings are suppressed.

Examples:

#ignore_warnings 203
while(TRUE) {
#ignore_warnings NONE
allenhuffman



Joined: 17 Jun 2019
Posts: 537
Location: Des Moines, Iowa, USA

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PostPosted: Mon Feb 03, 2020 11:06 am     Reply with quote
PCM programmer wrote:
#ignore_warnings 203
while(TRUE) {
#ignore_warnings NONE


Fantastic - being able to selectively toggle it around certain code is exactly what I was after. Thank you.

EDIT: Odd. The same test code I built last week that showed warnings in math.h is showing none today. I must have imagined it.
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?

Last edited by allenhuffman on Mon Feb 03, 2020 11:32 am; edited 1 time in total
allenhuffman



Joined: 17 Jun 2019
Posts: 537
Location: Des Moines, Iowa, USA

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PostPosted: Mon Feb 03, 2020 11:27 am     Reply with quote
In my case, we had some code where multiple cases would run the same code -- and this took care of those warnings:

Code:
#ignore_warnings 242
         case 'X':
         case 'x':
#ignore_warnings none


I got the 242 warning value from the error display (the help file didn't list numbers, just text/descriptions):

Code:
>>> Warning 242 "(path)\main.c" Line 657(21,22): May be missing a break


(I did ask the programmer why not do 'switch(toupper(key))' and just check uppercase, but he had some situations where lower and upper did different things, and some where they did the same.

But nice to now have less warnings.
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?
Ttelmah



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Posts: 19215

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PostPosted: Mon Feb 03, 2020 1:06 pm     Reply with quote
Honestly, 'toupper' uses a lot more code than the second switch...
allenhuffman



Joined: 17 Jun 2019
Posts: 537
Location: Des Moines, Iowa, USA

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PostPosted: Tue Feb 04, 2020 8:37 am     Reply with quote
Ttelmah wrote:
Honestly, 'toupper' uses a lot more code than the second switch...


I think it's more of a "Clean Code" approach, removing extra code a human has to deal with. Being exposed to that at my last job was quite enlightening, though it can't apply in every embedded situation (where CPU cycles might be more critical, or RAM/ROM space is limited).
_________________
Allen C. Huffman, Sub-Etha Software (est. 1990) http://www.subethasoftware.com
Embedded C, Arduino, MSP430, ESP8266/32, BASIC Stamp and PIC24 programmer.
http://www.whywouldyouwanttodothat.com ?
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