Smart Memory Allocation

Introduction

Smart Memory Allocation with Orphaned Buffer Detection

Few things are as embarrassing as a program that leaks, yet few errors are so easy to commit or as difficult to track down in a large, complicated program as failure to release allocated memory. SMARTALLOC replaces the standard C library memory allocation functions with versions which keep track of buffer allocations and releases and report all orphaned buffers at the end of program execution. By including this package in your program during development and testing, you can identify code that loses buffers right when it’s added and most easily fixed, rather than as part of a crisis debugging push when the problem is identified much later in the testing cycle (or even worse, when the code is in the hands of a customer). When program testing is complete, simply recompiling with different flags removes SMARTALLOC from your program, permitting it to run without speed or storage penalties.

In addition to detecting orphaned buffers, SMARTALLOC also helps to find other common problems in management of dynamic storage including storing before the start or beyond the end of an allocated buffer, referencing data through a pointer to a previously released buffer, attempting to release a buffer twice or releasing storage not obtained from the allocator, and assuming the initial contents of storage allocated by functions that do not guarantee a known value. SMARTALLOC’s checking does not usually add a large amount of overhead to a program (except for programs which use realloc() extensively; see below). SMARTALLOC focuses on proper storage management rather than internal consistency of the heap as checked by the malloc_debug facility available on some systems. SMARTALLOC does not conflict with malloc_debug and both may be used together, if you wish. SMARTALLOC makes no assumptions regarding the internal structure of the heap and thus should be compatible with any C language implementation of the standard memory allocation functions.

• Installing SMARTALLOC
• Squelching SMARTALLOC
• Living with Libraries
• SMARTALLOC Details
• When SMARTALLOC Is Disabled
• The alloc() Function
• Overlays and Underhandedness
• Test and Demonstration Program
• Invitation to Hack

Download smartall.zip (Zipped archive)

SMARTALLOC is provided as smartall.zip, a Zipped archive containing source code, documentation, and a Makefile to build the software under Unix.

Copying

SMARTALLOC is in the public domain. Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, without any conditions or restrictions. This software is provided ”as is“ without express or implied warranty.

by John Walker October 30th, 1998

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