bdls::MemoryUtil Struct Reference

#include <bdls_memoryutil.h>

Public Types
enum	Access {   k_ACCESS_NONE = 0 , k_ACCESS_READ = 0x1 , k_ACCESS_WRITE = 0x2 , k_ACCESS_EXECUTE = 0x4 ,   k_ACCESS_READ_WRITE = k_ACCESS_READ | k_ACCESS_WRITE , k_ACCESS_READ_EXECUTE = k_ACCESS_READ | k_ACCESS_EXECUTE , k_ACCESS_WRITE_EXECUTE = k_ACCESS_WRITE | k_ACCESS_EXECUTE , k_ACCESS_READ_WRITE_EXECUTE ,   BDESU_ACCESS_NONE = k_ACCESS_NONE , BDESU_ACCESS_READ = k_ACCESS_READ , BDESU_ACCESS_WRITE = k_ACCESS_WRITE , BDESU_ACCESS_EXECUTE = k_ACCESS_EXECUTE ,   BDESU_ACCESS_READ_WRITE = k_ACCESS_READ_WRITE , BDESU_ACCESS_READ_EXECUTE = k_ACCESS_READ_EXECUTE , BDESU_ACCESS_WRITE_EXECUTE = k_ACCESS_WRITE_EXECUTE , BDESU_ACCESS_READ_WRITE_EXECUTE = k_ACCESS_READ_WRITE_EXECUTE ,   ACCESS_READ = k_ACCESS_READ , ACCESS_WRITE = k_ACCESS_WRITE , ACCESS_EXECUTE = k_ACCESS_EXECUTE , ACCESS_NONE = k_ACCESS_NONE ,   ACCESS_READ_WRITE = k_ACCESS_READ_WRITE , ACCESS_READ_EXECUTE = k_ACCESS_READ_EXECUTE , ACCESS_WRITE_EXECUTE = k_ACCESS_WRITE_EXECUTE , ACCESS_READ_WRITE_EXECUTE = k_ACCESS_READ_WRITE_EXECUTE }

Static Public Member Functions
static int	pageSize ()
static int	protect (void *address, int numBytes, int mode)
static void *	allocate (int numBytes)
static int	deallocate (void *address)

Member Enumeration Documentation

Access

enum bdls::MemoryUtil::Access

Enumerator
k_ACCESS_NONE
k_ACCESS_READ
k_ACCESS_WRITE
k_ACCESS_EXECUTE
k_ACCESS_READ_WRITE
k_ACCESS_READ_EXECUTE
k_ACCESS_WRITE_EXECUTE
k_ACCESS_READ_WRITE_EXECUTE
BDESU_ACCESS_NONE
BDESU_ACCESS_READ
BDESU_ACCESS_WRITE
BDESU_ACCESS_EXECUTE
BDESU_ACCESS_READ_WRITE
BDESU_ACCESS_READ_EXECUTE
BDESU_ACCESS_WRITE_EXECUTE
BDESU_ACCESS_READ_WRITE_EXECUTE
ACCESS_READ
ACCESS_WRITE
ACCESS_EXECUTE
ACCESS_NONE
ACCESS_READ_WRITE
ACCESS_READ_EXECUTE
ACCESS_WRITE_EXECUTE
ACCESS_READ_WRITE_EXECUTE

Member Function Documentation

allocate()

static void * bdls::MemoryUtil::allocate ( int  numBytes )

static

Allocate an area of memory of the specified size numBytes, aligned on a page boundary. Return a pointer to allocated memory on success, and a null pointer otherwise.

Note

Note that the allocated memory is readable and writable, and read/write access to this memory, if revoked, must be restored before deallocation.

deallocate()

static int bdls::MemoryUtil::deallocate ( void *  address )

static

Deallocate a memory area at the specified address previously allocated with the allocate method. Return 0 on success, and a nonzero value otherwise.

Precondition

The behavior is undefined if read or write access to any memory in this area has been revoked and not restored.

Note

Note that deallocating memory does not change memory protection.

pageSize()

static int bdls::MemoryUtil::pageSize ( )

static

Return the memory page size of the platform.

protect()

static int bdls::MemoryUtil::protect ( void *  address, int  numBytes, int  mode  )

static

Change the access protection on a region of memory starting at the specified address and numBytes long, according to specified mode, making memory readable if (mode & ACCESS_READ) is nonzero and writable if (mode & ACCESS_WRITE) is nonzero. Return 0 on success, and a nonzero value otherwise.

Precondition

The behavior is undefined if addr is not aligned on a page boundary, if numBytes is not a multiple of pageSize(), or if numBytes is 0.

Note

Note that some platforms do not support certain protection modes, e.g., on some platforms the memory cannot be made writable but unreadable, or readable but non-executable. On these platforms the actual access protection set on the region might be more permissive than the specified one. Also note that most memory allocators do not expect memory protection on allocated memory to be changed, so you must reset protection back to ACCESS_READ_WRITE before releasing the memory.

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The documentation for this struct was generated from the following file:

• bdls_memoryutil.h