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# Safety Checks #
Eina safety checks are a set of macros designed 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 the program outright.
## Available Safety Checks ##
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(…)``
### EINA_SAFETY_ON_NULL_RETURN() ###
Use the ``EINA_SAFETY_ON_NULL_RETURN()`` function to return ``NULL``; this macro calls ``return`` if the given parameter is ``NULL``.
```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;
} ```
### EINA_SAFETY_ON_NULL_RETURN_VAL() ###
Use the ``EINA_SAFETY_ON_NULL_RETURN_VAL()`` function instead of the ``EINA_SAFETY_ON_NULL_RETURN()`` function to return a specific value; this macro returns the given value.
```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;
} ```
### EINA_SAFETY_ON_NULL_GOTO() ###
Use the ``EINA_SAFETY_ON_NULL_GOTO()`` function to call another function if a parameter is ``NULL``. This macro works similarly to the ``EINA_SAFETY_ON_NULL_RETURN()`` function except that it calls ``goto`` with the given function instead of ``return``.
```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;
} ```
### EINA_SAFETY_ON_TRUE_RETURN() ###
Eina also provides macros to check whether a given value is ``TRUE`` or ``FALSE``. 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.
## Further Reading ##
[The Safety Checks API](https://www.enlightenment.org/develop/legacy/api/c/start#group__Eina__Safety__Checks__Group.html) : A reference for the Safety Checks API.