Hallo!
I'm looking for a way to add custom messages to assert statements. I found this questions Add custom messages in assert? but the message is static there. I want to do something like this:
assert((0 < x) && (x < 10), std::string("x was ") + myToString(x));
When the assertion fails I want the normal output plus for example "x was 100".
You are out of luck here. The best way is to define your own assert
macro.
Basically, it can look like this:
#ifndef NDEBUG
# define ASSERT(condition, message) \
do { \
if (! (condition)) { \
std::cerr << "Assertion `" #condition "` failed in " << __FILE__ \
<< " line " << __LINE__ << ": " << message << std::endl; \
std::terminate(); \
} \
} while (false)
#else
# define ASSERT(condition, message) do { } while (false)
#endif
This will define the ASSERT
macro only if the no-debug macro NDEBUG
isn’t defined.
Then you’d use it like this:
ASSERT((0 < x) && (x < 10), "x was " << x);
Which is a bit simpler than your usage since you don’t need to stringify "x was "
and x
explicitly, this is done implicitly by the macro.