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Assertions in the Ecl

Description: how to utilise ecl's run-time and compile-time asserts/aborts.

Keywords: ecl errors assertions

Tutorial Level: BEGINNER

Run-Time Assert/Abort

These functions, because they are coupled with fallback macros for debug/ndebug modes, are the only functions in the ecl not namespaced inside the ecl namespace. Rather they are prefixed with ecl_.

The ecl_run_time_assert macro/function is a tool for conditional testing. It is governed by the presence of the NDEBUG macro. If NDEBUG is absent (either in your code or c-flagged by the compiler (-DNDEBUG) then run_time_assert will equate to a macro that defers to a null function pointer. This is the fastest means of bypassing debugged code.

If NDEBUG is defined, then ecl_run_time_assert will act as a conditional test via a function. If the test fails, it will output some data (that you have passed to the function) before finally aborting.

   1 int i = 3;
   2 int j = 2;
   3 ecl_run_time_assert(i < j, LOC, "Illegal context, need i < j");

The ecl_runtime_abort macro/function works similarly except that it does no conditional test and it is not negated by the presence of NDEBUG.

Compile-Time Assert

There is also a macro which works as a compile time equivalent of ecl_run_time_assert(). This macro is useful for checking template parameters mostly. When passed a logical condition which fails, an eye-catching COMPILE_TIME_FAILURE is reported in the compile log.

   1 ecl_compile_time_assert( 1 > 3 )

Corresponding failure is reported in a format similar to the example output shown below:

   1 test.cpp:47: error: invalid application ofsizeofto incomplete typeCOMPILE_TIME_FAILURE<false>’

2019-10-12 12:35