You are here:

C++/realloc equivalent in C++


Is there any function equivalent to "realloc" of C in C++?

Sushil Kumar , Thank you for your question.

Unfortunately, there is not.

If you know that the 'new' operator actually calls 'malloc', you can use 'realloc' safely. However, such code may not be portable to all computers, particularly across operating systems, due to differences in the C run-time libraries. You can redefine 'new' and 'delete' to call 'malloc' and 'free', but this may not work with all compilers.

Either create a new block, copy the data, then delete the old block, or write your program so that it does not require 'realloc' functionality.

Another possibility (that I use) is to write your own memory allocator. Then you can do lots of optimizations and support 'realloc' functionality.

David Spector


All Answers

Answers by Expert:

Ask Experts


David Spector


Highly knowledgeable in the C++ language, Visual C++ (MSVC), Windows API, documentation and other quality-assurance techniques, and debugging. Knowledgeable in MFC, COM, GUI design, and object-oriented design.


I have been a software engineer since 1965. I have been published. My specializations have been: biomedical programming, compiler implementation, and many kinds of Windows programming. I don't do Databases or other business-oriented stuff.

Windows?/DOS Developer's Journal, ACM SIGPLAN Notices, and Computer Science Press.

ICCP Systems Programming Certification
Master's degree equivalent in Computer Science

©2017 All rights reserved.