To get a trial key
fill out the form below
Team license
Enterprise license
** By clicking this button you agree to our Privacy Policy statement

Request our prices
New License
License Renewal
--Select currency--
USD
EUR
RUB
* By clicking this button you agree to our Privacy Policy statement

Free PVS-Studio license for Microsoft MVP specialists
** By clicking this button you agree to our Privacy Policy statement

To get the licence for your open-source project, please fill out this form
** By clicking this button you agree to our Privacy Policy statement

I am interested to try it on the platforms:
** By clicking this button you agree to our Privacy Policy statement

Message submitted.

Your message has been sent. We will email you at


If you haven't received our response, please do the following:
check your Spam/Junk folder and click the "Not Spam" button for our message.
This way, you won't miss messages from our team in the future.

>
>
How much memory can an application acce…

How much memory can an application access in Win32 and Win64?

Jan 23 2012
Author:

When developing a software product for a Windows-family operating system, you must keep in mind the restrictions imposed on sizes of data a program can declare and use.

Windows imposes the following 3 types of restrictions on applications:

  • Static data. The restriction is imposed on the size of the program source code itself and the size of statically allocated memory. In C++, such data is usually represented by global variables defined by outside procedures. The restriction concerning the size of statically allocated memory is 2 Gbytes both for 32-bit and 64-bit programs.
  • Dynamic data. This is data for which memory is being allocated while executing the program. In C++, this allocation is usually performed by the malloc function or new operator. In 32-bit programs the size of dynamically allocated memory is restricted to 2 Gbytes, in 64-bit programs to 8 Tbytes.
  • Stack data. Memory is allocated for this data when entering a procedure, and is released after exiting the procedure. The maximum size of program stack is 1 Gbyte for both 32-bit and 64-bit applications. (The stack size is defined by the linker and is 1 Mbyte by default)

For a 32-bit application launched in a 32-bit Windows, the total size of all the mentioned data types must not exceed 2 Gbytes. (Actually it is 1.75 Gbytes due to memory requirements of the operating system itself). A 32-bit program compiled with the switch /LARGEADDRESSAWARE:YES can allocate up to 3 Gbytes of memory if the 32-bit Windows is launched with the /3gb switch. The same 32-bit program launched in a 64-bit system can allocate about 4 Gbytes (actually about 3.5 Gbytes).

Note that the restrictions for maximum sizes of statically allocated memory and stack memory are the same for 32-bit and 64-bit Windows-applications. This is determined by the format of file type Portable Executable (PE), which is used in Windows to describe exe and dll files. You should keep in mind that these restrictions are imposed by the operating system itself, and do not depend on the compiler you are using.

References

Latest articles:

Poll:

Popular related articles
macOS 10.15 no longer supports 32-bit apps. What can you do?

Date: Oct 15 2019

Author: Sergey Khrenov

On October 7, 2019, Apple released a new version of its Mac operating system, macOS Catalina. Version 10.15 contains many changes and improvements. One of the significant is the complete phasing out …
If the coding bug is banal, it doesn't mean it's not crucial

Date: Apr 19 2017

Author: Andrey Karpov

Spreading the word about PVS-Studio static analyzer, we usually write articles for programmers. However, some things are seen by programmers quite one-sided. That is why there are project managers wh…
Detecting Overflows of 32-Bit Variables in Long Loops in 64-Bit Programs

Date: Mar 22 2016

Author: Andrey Karpov

One of the problems that 64-bit software developers have to face is overflows of 32-bit variables in very long loops. PVS-Studio code analyzer is very good at catching issues of this type (see the Vi…
Is it possible to run 64-bit applications in a 32-bit OS?

Date: Dec 08 2015

Author: Andrey Karpov

Nowadays 64-bit operating systems are very widespread. But 32-bit OS are still present on the market, in quite obvious quantities. A lot of modern program tools are developed to be run only in 64-bit…
How to Port a 9 Million Code Line Project to 64 bits?

Date: Aug 03 2015

Author: Evgenii Ryzhkov, Ilya Ivanov

Our team has recently finished porting one pretty large project (9 million code lines, 300 Mbytes of source files) to the 64-bit platform. It took us one year and a half. Although we are not permitte…

Comments (0)

Next comments
Unicorn with delicious cookie
Our website uses cookies to enhance your browsing experience.
Accept