bdls_memoryutil

Detailed Description

Outline

• Purpose
• Classes
• Description
  • Usage
    • Example 1: Basic Usage

Purpose

Provide a set of portable utilities for memory manipulation.

Classes

• bdls::MemoryUtil: struct which scopes memory system utilities.

Description

This component, bdls::MemoryUtil, defines a platform-independent interface for memory manipulation, providing utilities for querying page size, allocating/deallocating page-aligned memory, and utility to change memory protection.

Usage

This section illustrates intended use of this component.

Example 1: Basic Usage

First, allocate one page of memory.

int pageSize = bdls::MemoryUtil::pageSize();
char *data = (char*)bdls::MemoryUtil::allocate(pageSize);

Write into the allocated buffer.

data[0] = '1';

Make the memory write protected

bdls::MemoryUtil::protect(data, pageSize,
                          bdls::MemoryUtil::k_ACCESS_READ);

Verify that data still could be read.

assert('1' == data[0]);

Once again, try writing into the buffer. This should crash our process.

data[0] = '2';

Restore read/write access and free the allocated memory. Actually, this will never be executed, as the process has already crashed.

bdls::MemoryUtil::protect(data, pageSize,
                          bdls::MemoryUtil::k_ACCESS_READ_WRITE);
bdls::MemoryUtil::free(data);