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


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 {


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;


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
What is the real function of class - to export data? No, Real purpose of a class isn't to export data. Instead, it's to provide services. Class provides a way to abstract behav

We are now quite happy to use the basic mathematical expressions, however in engineering we use scientific functions i.e Sin , Cos  , ln etc . Within C we have the following functi

Define a user-defined data type (struct) called Car to represent a car in the context of a car dealership database. Car must have at least the following characteristics: Make Model

write a program for convert numbers upto 9 to alphabet? enter the inputis 666 means output is "0" lphabet

Write a program to find the area under the curve y = f(x) between x = a and x = b, integrate y = f(x) between the limits of a and b. The area under a curve between two points can b

write a cprogram to calculate fraction through recursion

array of class objects and single inheritance

Networking program development. 1.ARP protocol. 2.Switching HUB. 3.wireshark. 4.winpcap library. 5.C++ & MFC. 6.LAN evironment through switch and HUB(static ARP t

Your task in this project is to write a C program named layout.c which does text layout. This is a staged project, complete the stages in order. The maximum mark if you nish each

Develop a C++ program that uses a while to determine the gross pay (in Dollars) for each of several employees. The company pays “straight-time” for the first 40 hours worked by ea