How can one encourage his (older) compiler , C/C++ Programming

Q: How can one encourage his (older) compiler to check new to see automatically if it returns

NULL?      

A: His compiler eventually will.

If he contain an old compiler which doesn't auto magically perform the NULL test, he might force the runtime system to do the test through installing a "new handler" function. his "new handler" function might do anything he wish, such as throw an exception, delete some of the objects and return (wherein case operator new will retry the allocation), print a message & abort() the program, etc.

Here's a sample "new handler" which prints a message & throws an exception. The handler is installed by using std::set_new_handler():

#include // To obatin std::set_new_handler

#include // To obtain abort()

#include // To obtain std::cerr

class alloc_error : public std::exception {

public:

alloc_error() : exception() { }

};

void myNewHandler()

{

// this is own handler. It can do anything he wants. throw alloc_error();

}

int main()

{

std::set_new_handler(myNewHandler); // Install "new handler"

...

}

After the std::set_new_handler() line is executed, operator new will call your myNewHandler()

If it run out of memory. It means that new will never return NULL:

Fred* p = new Fred(); // No require to check if p is NULL

Note: If your compiler doesn't support exception handling, you can, as a final resort, change the line throw ...; to:

std::cerr << "try to allocate memory failed!" << std::endl;

abort();

Note: If some global/static object's constructor use new, this won't employ the myNewHandler() function since that constructor will get called before main() starts. Unluckily there's no convenient method to guarantee that the std::set_new_handler() will be called before the first use of new. For instance, even if you put the std::set_new_handler() call in the constructor of global object, still you don't know if the module ("compilation unit") which contains that global object will be elaborated in initial or in last or somewhere in between. Thus you still don't have any guarantee that your call of std::set_new_handler() will happen before any other global's constructor gets invoked.

Posted Date: 3/19/2013 8:39:36 AM | Location : United States







Related Discussions:- How can one encourage his (older) compiler , Assignment Help, Ask Question on How can one encourage his (older) compiler , Get Answer, Expert's Help, How can one encourage his (older) compiler Discussions

Write discussion on How can one encourage his (older) compiler
Your posts are moderated
Related Questions
find area uder the curve y=f(x) between x=a and x=b   #include float start_point, /* GLOBAL VARIABLES */ end_point, total_area; in

Can copy constructor admit an object of the same class as parameter, rather than reference of the object?

Operators in C++: All C operators are valid operators in C++ also.  Besides C++ has developed some new operators like Operators and their Expression: 1.      Logical op


1.1 A Few Notes: 1. Please test your program with various inputs prior to submission. 2. All group members must understand the entire project for interactive grading. Equal

write a grading program for a class with the following grading polices: a.there are two quizzes eaxh graded on the basis of 10 points b.there is ome midterm exam and one final exam

The for Loop For loop is the controlled form of loop. The general format of this : for( initialize ; test ; update)                  {                     statements;

Define the Char Data Type of C Language? The char defines characters. The char type will usually require only 1 byte of internal storage. Every char type has an equivalent inte


Intelligent homes are becoming increasingly popular as the cost/performance ratio of microcontrollers is continuously dropping.  These systems incorporate various transducers to de