Date: Sat, 11 Aug 2018 20:21:34 +0200 Subject: Initial commit --- docs/doxygen/nel/a03382.html | 328 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 328 insertions(+) create mode 100644 docs/doxygen/nel/a03382.html (limited to 'docs/doxygen/nel/a03382.html') diff --git a/docs/doxygen/nel/a03382.html b/docs/doxygen/nel/a03382.html new file mode 100644 index 00000000..1811e263 --- /dev/null +++ b/docs/doxygen/nel/a03382.html @@ -0,0 +1,328 @@ + + +NeL: NLMISC::CSharedMemory class Reference + + + +

NLMISC::CSharedMemory Class Reference

#include <shared_memory.h> +

Detailed Description

+Encapsulation of shared memory APIs. Using file mapping under Windows, System V shared memory (shm) under Linux.

+Note: under Linux, an option could be added to prevent a segment to be swapped out.

Author:: Olivier Cado
+Nevrax France

Date:: 2002

+ +

+Definition at line 68 of file shared_memory.h. + + + + + + + + + + +

Static Public Member Functions
void * accessSharedMemory (TSharedMemId sharedMemId)
bool closeSharedMemory (void *accessAddress)
void * createSharedMemory (TSharedMemId sharedMemId, uint32 size)
void destroySharedMemory (TSharedMemId sharedMemId, bool force=false)
+

Member Function Documentation

+ + + + +
+ + + + + + + + + + +
void * NLMISC::CSharedMemory::accessSharedMemory ( TSharedMemId sharedMemId ) [static]
+
+ + + + + +
+ + + +
+Get access to an existing shared memory segment. The id must be used.
Returns:
Access address of the segment. Its size was determined at the creation.
+ +
+Definition at line 100 of file shared_memory.cpp. +
+References NLMISC::TSharedMemId. +
+
00101 { +00102 #ifdef NL_OS_WINDOWS +00103 +00104 // Open the existing file mapping by name +00105 HANDLE hMapFile = OpenFileMapping( FILE_MAP_ALL_ACCESS, false, sharedMemId ); +00106 if ( hMapFile == NULL ) +00107 return NULL; +00108 //nldebug( "SHDMEM: Opening smid %s --> mapFile %p", sharedMemId, hMapFile ); +00109 +00110 // Map the file into memory address space +00111 void *accessAddress = MapViewOfFile( hMapFile, FILE_MAP_ALL_ACCESS, 0, 0, 0 ); +00112 AccessAddressesToHandles.insert( make_pair( accessAddress, hMapFile ) ); +00113 return accessAddress; +00114 +00115 #else +00116 +00117 // Open an existing shared memory segment +00118 int shmid = shmget( sharedMemId, 0, 0666 ); +00119 if ( shmid == -1 ) +00120 return NULL; +00121 +00122 // Map the segment into memory address space +00123 void *accessAddress = (void*)shmat( shmid, 0, 0 ); +00124 if ( accessAddress == (void*)-1 ) +00125 return NULL; +00126 else +00127 return accessAddress; +00128 +00129 #endif +00130 } +

+

+ + + + +
+ + + + + + + + + + +
bool NLMISC::CSharedMemory::closeSharedMemory ( void * accessAddress ) [static]
+
+ + + + + +
+ + + +
+Close a shared memory segment, given the address returned by createSharedMemory() or accessSharedMemory(). Must be called by each process that called createSharedMemory() or accessSharedMemory(). +
+Definition at line 136 of file shared_memory.cpp. +
+References nlwarning. +
+
00137 { +00138 #ifdef NL_OS_WINDOWS +00139 +00140 bool result = true; +00141 +00142 // Unmap the file from memory address space +00143 if ( UnmapViewOfFile( accessAddress ) == 0 ) +00144 { +00145 nlwarning( "SHDMEM: UnmapViewOfFile failed: error %u", GetLastError() ); +00146 result = false; +00147 } +00148 +00149 // Close the corresponding handle +00150 map<void*,HANDLE>::iterator im = AccessAddressesToHandles.find( accessAddress ); +00151 if ( im != AccessAddressesToHandles.end() ) +00152 { +00153 //nldebug( "SHDMEM: CloseHandle mapFile %u", (*im).second ); +00154 if ( ! CloseHandle( (*im).second ) ) +00155 nlwarning( "SHDMEM: CloseHandle failed: error %u, mapFile %u", GetLastError(), (*im).second ); +00156 AccessAddressesToHandles.erase( im ); +00157 return result; +00158 } +00159 else +00160 { +00161 return false; +00162 } +00163 +00164 #else +00165 +00166 // Detach the shared memory segment +00167 return ( shmdt( accessAddress ) != -1 ); +00168 +00169 #endif +00170 } +

+

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
void * NLMISC::CSharedMemory::createSharedMemory ( TSharedMemId sharedMemId,
uint32 size
) [static]
+
+ + + + + +
+ + + +
+Create a shared memory segment and get access to it. The id must not be used. The id 0x3a732235 is used by the NeL memory manager.
Returns:
Access address of the segment of the choosen size
+ +
+Definition at line 55 of file shared_memory.cpp. +
+References nlwarning, NLMISC::SharedMemIdsToShmids, size, NLMISC::TSharedMemId, and uint32. +
+
00056 { +00057 #ifdef NL_OS_WINDOWS +00058 +00059 // Create a file mapping backed by the virtual memory swap file (not a data file) +00060 HANDLE hMapFile = CreateFileMapping( INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, size, sharedMemId ); +00061 if ( (hMapFile == NULL) || (GetLastError() == ERROR_ALREADY_EXISTS) ) +00062 { +00063 nlwarning( "SHDMEM: Cannot create file mapping: error %u, mapFile %p", GetLastError(), hMapFile ); +00064 return NULL; +00065 } +00066 //else +00067 // nldebug( "SHDMEM: Creating smid %s --> mapFile %p", sharedMemId, hMapFile ); +00068 +00069 +00070 // Map the file into memory address space +00071 void *accessAddress = MapViewOfFile( hMapFile, FILE_MAP_ALL_ACCESS, 0, 0, 0 ); +00072 AccessAddressesToHandles.insert( make_pair( accessAddress, hMapFile ) ); +00073 /*if ( accessAddress == NULL ) +00074 { +00075 nlwarning( "SHDMEM: Cannot map view of file: error %u", GetLastError() ); +00076 }*/ +00077 return accessAddress; +00078 +00079 #else +00080 +00081 // Create a shared memory segment +00082 int shmid = shmget( sharedMemId, size, IPC_CREAT | IPC_EXCL | 0666 ); +00083 if ( shmid == -1 ) +00084 return NULL; +00085 SharedMemIdsToShmids.insert( make_pair( sharedMemId, shmid ) ); +00086 +00087 // Map the segment into memory address space +00088 void *accessAddress = (void*)shmat( shmid, 0, 0 ); +00089 if ( accessAddress == (void*)-1 ) +00090 return NULL; +00091 else +00092 return accessAddress; +00093 #endif +00094 } +

+

+ + + + +
+ + + + + + + + + + + + + + + + + + + +
void NLMISC::CSharedMemory::destroySharedMemory ( TSharedMemId sharedMemId,
bool force = false
) [static]
+
+ + + + + +
+ + + +
+Destroy a shared memory segment (must be called by the process that created the segment, not by the accessors).
+"Rescue feature": set "force" to true if a segment was created and left out of control (meaning a new createSharedMemory() with the same sharedMemId fails), but before, make sure the segment really belongs to you!
+Note: this method does nothing under Windows, destroying is automatic. +
+Definition at line 177 of file shared_memory.cpp. +
+References NLMISC::SharedMemIdsToShmids, and NLMISC::TSharedMemId. +
+
00178 { +00179 #ifndef NL_OS_WINDOWS +00180 // Set the segment to auto-destroying (when the last process detaches) +00181 map<TSharedMemId,int>::iterator im = SharedMemIdsToShmids.find( sharedMemId ); +00182 if ( im != SharedMemIdsToShmids.end() ) +00183 { +00184 // Destroy the segment created before +00185 shmctl( (*im).second, IPC_RMID, 0 ); +00186 SharedMemIdsToShmids.erase( im ); +00187 } +00188 else if ( force ) +00189 { +00190 // Open and destroy the segment +00191 int shmid = shmget( sharedMemId, 0, 0666 ); +00192 if ( shmid != -1 ) +00193 { +00194 // Destroy the segment +00195 shmctl( shmid, IPC_RMID, 0 ); +00196 } +00197 } +00198 #endif +00199 } +

+

The documentation for this class was generated from the following files:

Generated on Tue Mar 16 13:32:41 2004 for NeL by + +

+1.3.6

+ + -- cgit v1.2.1


Static Public Member Functions
void *	accessSharedMemory (TSharedMemId sharedMemId)
bool	closeSharedMemory (void *accessAddress)
void *	createSharedMemory (TSharedMemId sharedMemId, uint32 size)
void	destroySharedMemory (TSharedMemId sharedMemId, bool force=false)