Generation and processing of exceptions using integer types is a bad practice of C++ programming. You should use more informative types for these purposes, for example types derived from the class std::exception. But sometimes you have to deal with a low-quality code like this:
char *ptr1;
char *ptr2;
try {
try {
throw ptr2 - ptr1;
}
catch (int) {
std::cout << 'catch 1: on x86' << std::endl;
}
}
catch (ptrdiff_t) {
std::cout << 'catch 2: on x64' << std::endl;
}You should be very attentive and avoid generation or processing of exceptions using memsize-types because it may result in changes of program logic. To correct this code you may replace 'catch (int)' with 'catch (ptrdiff_t)'. A more correct way is to use a special class to pass the information about an error that has occurred.
We have not encountered errors of this type in practice yet but the tool PVS-Studio can detect them. The diagnostic message V115 will be shown when an exception is generated with the help of a memsize-type, while the warning V116 will be generated when a memsize-type is used in catch operator.
The course authors: Andrey Karpov (karpov@viva64.com), Evgeniy Ryzhkov (evg@viva64.com).
The rightholder of the course 'Lessons on development of 64-bit C/C++ applications' is OOO 'Program Verification Systems'. The company develops software in the sphere of source program code analysis. The company's site: http://www.viva64.com.
