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I have third-party static library built with Enable C++ Exceptions set to No (/EH flag not specified). What are the consequences to calling into it from code built with C++ exceptions enabled (/EHa)? If a Structured Exception is thrown from within the library, will the function provided to _set_se_translator by the main application be reliably called? (My experiments show that it will, but just wondering if this is defined behavior).
Are there any other considerations when mixing /EH exception handing models?
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Exception handling is the process of responding to unwanted or unexpected events when a computer program runs. Exception handling deals with these events to avoid the program or system crashing, and without this process, exceptions would disrupt the normal operation of a program.
5.1 Understanding Exception Handling Exceptions are anomalies that occur during the normal flow of a program and prevent it from continuing. These anomalies--user, logic, or system errors--can be detected by a function. If the detecting function cannot deal with the anomaly, it "throws" an exception.
When the debugger breaks, it shows you where the exception was thrown. You can also add or delete exceptions. With a solution open in Visual Studio, use Debug > Windows > Exception Settings to open the Exception Settings window. Provide handlers that respond to the most important exceptions.
Exception handling in C++ consists of three keywords: try, throw and catch: The try statement allows you to define a block of code to be tested for errors while it is being executed. The throw keyword throws an exception when a problem is detected, which lets us create a custom error.
Calling into code which does not have exceptions enabled shouldn't produce any problems -- this is no different than calling an external C function or something of that nature.
Calling from code which does not have exceptions enabled (into exception enabled code) will probably not contain the correct stack unwinding semantics in the exception disabled code, which means you'll be breaking invariants of that code, unless it was specifically designed to work with exceptions. (For example, some libraries (e.g. ANTLR) allocate all memory in a block and have the user code free everything at once, allowing exceptions to be used without leaking even though they themselves do not use exceptions).
Raymond Chen has quite an article about the innards of how C++'s exception handling works on MSVC++. Long story short, it's built on top of Windows' SEH. Therefore it should behave similarly to what happens if you throw a SEH exception in e.g. C code. (However, I've not verified this myself)
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