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===== Safety Checks =====

Eina safety checks are a set of macros that can be used to check for
parameters or values that must never occur. The concept is similar to the
''assert()'' function, but safety checks log the parameter or value and return
instead of aborting your program.

=== Related Info ===

  * [[https://build.enlightenment.org/job/nightly_efl_gcc_x86_64/lastSuccessfulBuild/artifact/doc/html/group__Eina__Safety__Checks__Group.html|Safety Checks API]]

The following safety checks are available:

   * ''EINA_SAFETY_ON_NULL_RETURN(exp)''
   * ''EINA_SAFETY_ON_NULL_RETURN_VAL(exp, val)''
   * ''EINA_SAFETY_ON_NULL_GOTO(exp, label)''
   * ''EINA_SAFETY_ON_TRUE_RETURN(exp)''
   * ''EINA_SAFETY_ON_TRUE_RETURN_VAL(exp, val)''
   * ''EINA_SAFETY_ON_TRUE_GOTO(exp, label)''
   * ''EINA_SAFETY_ON_FALSE_RETURN(exp)''
   * ''EINA_SAFETY_ON_FALSE_RETURN_VAL(exp, val)''
   * ''EINA_SAFETY_ON_FALSE_GOTO(exp, label)''
   * ''EINA_ARG_NONNULL(...)''

To return if a variable is ''NULL'', use the ''EINA_SAFETY_ON_NULL_RETURN()''
function. This macro calls return if the given parameter is ''NULL''.

<code c>
Eina_Bool myfunction(char *param)
{
   // If my param is NULL, EINA_SAFETY_ON_NULL_RETURN calls "return"
   EINA_SAFETY_ON_NULL_RETURN(param);

   printf("My pram is : %s\n", param);

   return EINA_TRUE;
}
</code>

To return a specific value, use the ''EINA_SAFETY_ON_NULL_RETURN_VAL()''
function instead of the ''EINA_SAFETY_ON_NULL_RETURN()'' function. This macro
returns the given value.

<code c>
Eina_Bool void myfunction(char *param)
{
   // If the parameter is NULL, return EINA_FALSE;
   EINA_SAFETY_ON_NULL_RETURN_VAL(param, EINA_FALSE);
   printf("My pram is : %s\n", param);

   return EINA_TRUE;
}
</code>

To call another function if a parameter is ''NULL'', use the
''EINA_SAFETY_ON_NULL_GOTO()'' function. This macro works similarly to the
''EINA_SAFETY_ON_NULL_RETURN()'' function except that it calls goto with the
given function instead of return.

<code c>
static void isnullcb()
{
   printf("The parameter is NULL\n");
}
Eina_Bool void myfunction(char *param)
{
   // If the parameter is NULL we return EINA_FALSE;
   EINA_SAFETY_ON_NULL_GOTO(param, isnullcb);
   printf("My pram is : %s\n", param);

   return EINA_TRUE;
}
</code>

Eina also provides macros that check whether a given value is ''TRUE'' or
''FALSE''. For example, to call return if a given value is ''TRUE'', use the
''EINA_SAFETY_ON_TRUE_RETURN()'' function. To call "goto" in a given function
if a given value is ''TRUE'', use the ''EINA_SAFETY_ON_NULL_GOTO()'' function.

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