MISRA.FUNC.UNUSEDRET.2012

The value returned by a function having non-void return type shall be used.

MISRA C 2012 Rule 17.7: The return value of a non-void function shall be used

Category: Required

Analysis: Decidable, Single Translation Unit

Applies to: C90, C99

Rationale

It is possible to call a function without using the return value, which may be an error. If the return value of a function is intended not to be used explicitly, it should be cast to the void type. This has the effect of using the value without violating Rule 2.2.

Example

uint16_t func ( uin t16_t para1 ) 
{
   return para1;
}
uint16_t x;

void discarded ( uint16_t para2 ) 
{
  func ( para2 );                /* Non-compliant - value discarded */ 
  ( void ) func ( para2 );       /* Compliant                       */ 
  x = func ( para2 );            /* Compliant                       */ 
}

See also

Dir 4.7, Rule 2.2