VirtualAlloc2 Perform (Memoryapi.h) > 자유게시판

Reserves, commits, or adjustments the state of a region of memory inside the digital deal with house of a specified process (allotted memory is initialized to zero). The handle to a course of. The function allocates memory inside the digital address space of this process. OPERATION access proper. For more info, see Process Security and Entry Rights. If Course of is NULL, the function allocates memory for Memory Wave Audio the calling course of. The pointer that specifies a desired beginning handle for the region of pages that you just wish to allocate. If BaseAddress is NULL, the function determines the place to allocate the region. Necessities structure should include all zeroes, and the bottom address have to be a a number of of the system allocation granularity. To find out the allocation granularity, use the GetSystemInfo operate. If this tackle is within an enclave that you have not initialized by calling InitializeEnclave, VirtualAlloc2 allocates a page of zeros for the enclave at that tackle. The page should be beforehand uncommitted, and is not going to be measured with the EEXTEND instruction of the Intel Software program Guard Extensions programming mannequin.

Handle error. That's true for enclaves that do not help dynamic memory administration (i.e. SGX1). SGX2 enclaves will permit allocation, and the page have to be accepted by the enclave after it has been allotted. The size of the area of memory to allocate, in bytes. The scale must all the time be a a number of of the page dimension. Measurement. This implies, for example, that a 2-byte range that straddles a page boundary causes the perform to allocate both pages. The type of memory allocation. This parameter should include one of the next values. RESERVE and a non-NULL BaseAddress fails until the whole range has already been reserved. An attempt to commit a web page that is already dedicated doesn't trigger the function to fail. This implies that you would be able to commit pages without first determining the present commitment state of each web page. Other memory allocation features, such as malloc and LocalAlloc, cannot use reserved memory till it has been released.

After you change a placeholder with a private allocation, to free that allocation again to a placeholder, see the dwFreeType parameter of VirtualFree and VirtualFreeEx. A placeholder is a sort of reserved Memory Wave Audio region. A placeholder is a type of reserved memory region. RESET will include zeros. If you would like the vary to contain zeros, decommit the memory after which recommit it. RESET, Memory Wave the VirtualAlloc2 operate ignores the value of fProtect. RESET and the range of memory is mapped to a file. A shared view is only acceptable if it is mapped to a paging file. This worth cannot be used with another worth. RESET earlier, the habits is undefined. RESET, the VirtualAlloc2 perform ignores the worth of PageProtection. This parameter may specify the following values as indicated. The dimensions and alignment must be a multiple of the massive-web page minimum. To acquire this value, use the GetLargePageMinimum function. A 64K page is a area of memory that is 64K in measurement, nearly and bodily contiguous, and just about and physically aligned on a 64K boundary.

PAGES is pageable, and physical pages backing the memory are allotted on demand (on the time of entry). PAGES allocation could also be mapped using non-contiguous small pages instead. NONPAGED attribute, the allocation will likely be mapped utilizing non-paged 64K pages. In that case, if contiguous 64K pages cannot be obtained, the allocation will fail. PAGES is specified, the size and BaseAddress parameters must each be multiples of 64K (BaseAddress may be NULL). RESERVE and no other values. The memory safety for the region of pages to be allotted. If the pages are being committed, you'll be able to specify any one of many memory safety constants. PARAMETER. Every of those extended parameter values can itself have a type area of either MemExtendedParameterAddressRequirements or MemExtendedParameterNumaNode. If no MemExtendedParameterNumaNode prolonged parameter is provided, then the habits is the same as for the VirtualAlloc/MapViewOfFile features (that is, the popular NUMA node for the bodily pages is set based on the best processor of the thread that first accesses the memory).

The variety of extended parameters pointed to by ExtendedParameters. If the perform succeeds, the return worth is the base address of the allocated region of pages. If the operate fails, the return value is NULL. To get extended error information, name GetLastError. This API provides specialized strategies for managing virtual memory in help of high-performance games and server purposes. For example, placeholders allow a reserved memory vary to be explicitly partitioned, overlaid, and Memory Wave re-mapped; this can be used to implement arbitrarily extendable areas or virtual memory ring buffers. VirtualAlloc2 also allows for allocating memory with a selected memory-alignment. Every page has an related page state. VirtualAlloc2 can commit pages that are already dedicated, but can't reserve pages which might be already reserved. This means you may commit a spread of pages, no matter whether they have already been committed, and the operate is not going to fail. In general however, solely a minimal range of principally uncommitted pages must be specified, as a result of committing a large number of pages which might be already committed can cause the VirtualAlloc2 call to take for much longer.