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
Write a Program that illustrate creation of a data file? Here is a program to generate a Fibonacci series and write it into a Data file. # include main() { FILE *fpt;



The files are meteorological radar data whose decompression is badly needed for relative study. Please contact Kathy Lee (Email: ; Cell phone: 0086 15701799056) or Mr. Zhu (Email:

While spending the summer as a surveyor’s assistant, you decide to write a program that transforms compass headings in degrees (0-360) to compass bearings. A compass bearing consis

Aim: To implement a program to display a rectangle, circle and triangle. Code:                       class shape {             public:                         vir

for object, malloc allocates memory in heap however doesn't invoke object's constructor to initialize the object. new allocates memory & also invokes constructor to initialize the

application problem of tower of hanoi

I really have a hard time analyzing how to write a code in C. It''s all bout Time Departure and we must used a 24 hour clock. Can u help me?

i need expression and its types with example programs in c++