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This function provides information about a range of pages in the virtual address space of the calling process.
DWORD VirtualQuery( LPCVOID lpAddress , PMEMORY_BASIC_INFORMATION lpBuffer , DWORD dwLength );
Parameters
- lpAddress
- Pointer to the base address of the region of pages to be queried. This value is rounded down to the next page boundary. To determine the size of a page on the host computer, use the GetSystemInfofunction.
- lpBuffer
- Pointer to a MEMORY_BASIC_INFORMATIONstructure in which information about the specified page range is returned.
- dwLength
- Specifies the size, in bytes, of the buffer pointed to by the
lpBufferparameter.
Return Values
The actual number of bytes returned in the information buffer indicates success.
Remarks
VirtualQueryprovides information about a region of consecutive pages beginning at a specified address that share the following attributes:
- The state of all pages is the same with the MEM_COMMIT, MEM_RESERVE, MEM_FREE, MEM_PRIVATE, MEM_MAPPED, or MEM_IMAGE flag.
- If the initial page is not free, all pages in the region are part of the same initial allocation of pages reserved by a call to the VirtualAllocfunction.
- The access of all pages is the same with the PAGE_READONLY,
PAGE_READWRITE, PAGE_NOACCESS, PAGE_WRITECOPY, PAGE_EXECUTE,
PAGE_EXECUTE_READ, PAGE_EXECUTE_READWRITE, PAGE_EXECUTE_WRITECOPY,
PAGE_GUARD, or PAGE_NOCACHE flag.
The VirtualQueryfunction determines the attributes of the first page in the region and then scans subsequent pages until it scans the entire range of pages or until it encounters a page with a nonmatching set of attributes. The function returns the attributes and the size, in bytes, of the region of pages with matching attributes. For example, if there is a 20 MB region of free memory and VirtualQueryis called on a page that is 10 MB into the region, the function will obtain a state of MEM_FREE and a size of 10 MB.
Requirements
Runs on Versions Defined in Include Link to Windows CE OS 1.0 and later Winbase.h Coredll.lib Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.
See Also
GetSystemInfo, VirtualAlloc, MEMORY_BASIC_INFORMATION