QA C Help - Rule 16.2

		MISRA-C:2004 Rule 16.2: (Required)			Functions shall not call themselves, either directly or indirectly.

This means that recursive function calls cannot be used in safety-related systems. Recursion carries with it the danger of exceeding available stack space, which can be a serious error. Unless recursion is very tightly controlled, it is not possible to determine before execution what the worst-case stack usage could be.

Example Code:


#include "misra.h"
#include "m2cmex.h"

static void test_1602a( S16 x );
static void test_1602b( S16 x );
static void test_1602c( S16 x );
static void test_1602d( S16 x );
static void test_1602e( S16 x );


extern S16 test_1602( void )
{
   test_1602a( 5 );
   test_1602e( 5 );
   return 1;
}

static void test_1602a( S16 x )
{
   if ( x > 0 )
   {
      --x;
      test_1602b( x );
   }
}

static void test_1602b( S16 x )
{
   if ( x > 0 )
   {
      --x;
      test_1602c( x );
   }
}

static void test_1602c( S16 x )
{
   if ( x > 0 )
   {
      --x;
      test_1602d( x );
   }
}

static void test_1602d( S16 x )
{
   if ( x > 0 )
   {
      --x;
      test_1602a( x );
   }
}

static void test_1602e( S16 x )
{
   if ( x > 0 )
   {
      --x;
      test_1602e( x );                /* MISRA Violation */
   }
}

QAC messages that encompass this guideline:

1520 Functions are indirectly recursive.

3670 Recursive call to function containing this call.

(c) The Motor Industry Research Association, 2004

QA C Source Code Analyser 8.1.2
MISRA-C:2004 Compliance Module 3.2
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1520	Functions are indirectly recursive.
3670	Recursive call to function containing this call.