Safety Checks
[Tools]

Safety checks are a set of macros to check for parameters or values that should never happen, it is similar in concept to assert(), but will log and return instead of abort() your program. More...

Defines
#define	EINA_SAFETY_ON_NULL_RETURN(exp)   do { (void)(!(exp)); } while (0)
#define	EINA_SAFETY_ON_NULL_RETURN_VAL(exp, val)   do { if (0 && !(exp)) { (void)val; } } while (0)
#define	EINA_SAFETY_ON_NULL_GOTO(exp, label)   do { if (0 && (exp) == NULL) { goto label; } } while (0)
#define	EINA_SAFETY_ON_TRUE_RETURN(exp)   do { (void)(exp); } while (0)
#define	EINA_SAFETY_ON_TRUE_RETURN_VAL(exp, val)   do { if (0 && (exp)) { (void)val; } } while (0)
#define	EINA_SAFETY_ON_TRUE_GOTO(exp, label)   do { if (0 && (exp)) { goto label; } } while (0)
#define	EINA_SAFETY_ON_FALSE_RETURN(exp)   do { (void)(!(exp)); } while (0)
#define	EINA_SAFETY_ON_FALSE_RETURN_VAL(exp, val)   do { if (0 && !(exp)) { (void)val; } } while (0)
#define	EINA_SAFETY_ON_FALSE_GOTO(exp, label)   do { if (0 && !(exp)) { goto label; } } while (0)
Functions
Eina_Bool	eina_safety_checks_init (void)
Variables
Eina_Error	EINA_ERROR_SAFETY_FAILED
	Error identifier corresponding to safety check failure.

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Detailed Description

Safety checks are a set of macros to check for parameters or values that should never happen, it is similar in concept to assert(), but will log and return instead of abort() your program.

Warning:

eina_safety_checks.h should only be included by source files, after all other includes and before the source file specific includes. By source file specific includes we mean those that define the functions that are being checked. The reason for such complexity is the trick to avoid compiler optimizations. If compilers are told that some given function will never receive NULL (EINA_ARG_NONNULL(), then compiler will emit a warning if it detects so (good!) but will remove any checks for that condition as it believes it will never happen, removing all safety checks! By including eina_safety_checks.h it will redefine EINA_ARG_NONNULL() to void and compiler warning will not be emitted, but checks will be there. The files already processed with the old macro EINA_ARG_NONNULL() will still work and emit the warnings.

 // all these files will emit warning from EINA_ARG_NONNULL()
 #include <Evas.h>  // third party headers
 #include <Ecore.h>
 #include <eina_error.h> // eina own header

 #include <eina_safety_checks.h>
 // all these files below will NOT emit warning from EINA_ARG_NONNULL(),
 // but this is required to have the functions defined there to be checked
 // for NULL pointers
 #include "my_functions1.h"
 #include "my_functions2.h"

Since these cases should never happen, one may wantto keep safety checks enabled during tests but disable then during deploy, not doing any checks at all. This is a common requirement for embedded systems. Whenever to check or not should be set during compile time by using --disable-safety-checks or --enable-safety-checks options to configure script.

Whenever these macros capture an error, EINA_LOG_ERR() will be called and eina_error set to EINA_ERROR_SAFETY_FAILED and can be checked with eina_error_get() after call.

See also:

EINA_SAFETY_ON_NULL_RETURN(), EINA_SAFETY_ON_NULL_RETURN_VAL() and other macros.