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virtualMemory.h
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1 //
2 // Copyright 2019 Pixar
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4 // Licensed under the Apache License, Version 2.0 (the "Apache License")
5 // with the following modification; you may not use this file except in
6 // compliance with the Apache License and the following modification to it:
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24 #ifndef PXR_BASE_ARCH_VIRTUAL_MEMORY_H
25 #define PXR_BASE_ARCH_VIRTUAL_MEMORY_H
26 
27 /// \file arch/virtualMemory.h
28 /// \ingroup group_arch_SystemFunctions
29 /// Architecture dependent routines for virtual memory.
30 
31 #include "pxr/pxr.h"
32 #include "pxr/base/arch/api.h"
33 
34 #include <cstddef>
35 
37 
38 /// Reserve \p numBytes bytes of virtual memory. Call ArchCommitVirtualMemory()
39 /// on subranges to write to and read from the memory. Return nullptr in case
40 /// of an error; check errno.
41 ARCH_API void *
42 ArchReserveVirtualMemory(size_t numBytes);
43 
44 /// Make the range of \p numBytes bytes starting at \p start available for
45 /// reading and writing. The range must be within one previously reserved by
46 /// ArchReserveVirtualMemory(). It is not an error to commit a range that was
47 /// previously partly or fully committed. Return false in case of an error;
48 /// check errno.
49 ARCH_API bool
50 ArchCommitVirtualMemoryRange(void *start, size_t numBytes);
51 
52 /// Return memory obtained with ArchReserveVirtualMemory() to the system. The
53 /// \p start argument must be the value returned from a previous call to
54 /// ArchReserveVirtualMemory, and \p numBytes must match the argument from that
55 /// call. Memory within the range may not be accessed after this call. Return
56 /// false in case of an error; check errno.
57 ARCH_API bool
58 ArchFreeVirtualMemory(void *start, size_t numBytes);
59 
60 /// Memory protection options, see ArchSetMemoryProtection().
66 };
67 
68 /// Change the memory protection on the pages containing \p start and \p start +
69 /// \p numBytes to \p protection. Return true if the protection is changed
70 /// successfully. Return false in case of an error; check errno. This function
71 /// rounds \p start to the nearest lower page boundary. On POSIX systems,
72 /// ArchProtectReadWrite and ArchProtectReadWriteCopy are the same, on Windows
73 /// they differ but the Windows API documentation does not make it clear what
74 /// using ReadWrite means for a private file-backed mapping.
75 ARCH_API bool
76 ArchSetMemoryProtection(void const *start, size_t numBytes,
77  ArchMemoryProtection protection);
78 
80 
81 #endif // PXR_BASE_ARCH_VIRTUAL_MEMORY_H
GLuint start
Definition: glcorearb.h:475
ARCH_API bool ArchCommitVirtualMemoryRange(void *start, size_t numBytes)
ARCH_API bool ArchSetMemoryProtection(void const *start, size_t numBytes, ArchMemoryProtection protection)
PXR_NAMESPACE_CLOSE_SCOPE PXR_NAMESPACE_OPEN_SCOPE
Definition: path.h:1432
PXR_NAMESPACE_OPEN_SCOPE ARCH_API void * ArchReserveVirtualMemory(size_t numBytes)
#define PXR_NAMESPACE_CLOSE_SCOPE
Definition: pxr.h:91
ARCH_API bool ArchFreeVirtualMemory(void *start, size_t numBytes)
ArchMemoryProtection
Memory protection options, see ArchSetMemoryProtection().
Definition: virtualMemory.h:61
#define ARCH_API
Definition: api.h:40