I don\'t quite get why do we need to make a distinction between error code (std::error_code)
and an error condition(std::error_condition)
, aren\'t they
From http://en.cppreference.com/w/cpp/error/error_condition
std::error_condition is a platform-independent error code. Like std::error_code, it is uniquely identified by an integer value and a std::error_category, but unlike std::error_code, the value is not platform-dependent.
So, the advantage is your error code isn't specific to the platform you're working on when using std::error:condition
.
With an std::error_code
Each std::error_code object holds a pair of error code originating from the operating system, or some low-level interface
So, the error_code
will reference something specific to your platform, a piece of hardware etc etc.
It may be advantageous to use both. The error_condition
is the "portable abstraction" so would be the generic error message to give to the user and the error_code
would be the platform dependent information that would be useful for specific debug.
A typical implementation [of error_condition] holds one integer data member (the value) and a pointer to an std::error_category.
The simplest answer to this question I found here: http://blog.think-async.com/2010/04/system-error-support-in-c0x-part-5.html.
- class
std::error_code
- represents a specific error value returned by an operation (such as a system call).- class
std::error_condition
- something that you want to test for and, potentially, react to in your code.
I think it is applicable for C++11 too.