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@@ -569,24 +569,78 @@ On error, -1 is returned, and \var{IPCError} is set.
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\Declaration
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Function shmat (shmid:longint; shmaddr:pchar; shmflg:longint):pchar;
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\Description
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+\var{shmat} attaches a shared memory block with identified \var{shmid}
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+to the current process. The function returns a pointer to the shared memory
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+block.
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+
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+If \var{shmaddr} is \var{Nil}, then the system chooses a free unmapped
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+memory region, as high up in memory space as possible.
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+
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+If \var{shmaddr} is non-nil, and \var{SHM\_RND} is in \var{shmflg}, then
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+the returned address is \var{shmaddr}, rounded down to \var{SHMLBA}.
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+If \var{SHM\_RND} is not specified, then \var{shmaddr} must be a
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+page-aligned address.
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+
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+The parameter \var{shmflg} can be used to control the behaviour of the
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+\var{shmat} call. It consists of a ORed combination of the following
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+costants:
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+\begin{description}
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+\item[SHM\_RND] The suggested address in \var{shmaddr} is rounded down to
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+\var{SHMLBA}.
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+\item[SHM\_RDONLY] the shared memory is attached for read access only.
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+Otherwise the memory is attached for read-write. The process then needs
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+read-write permissions to access the shared memory.
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+\end{description}
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\Errors
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+If an error occurs, -1 is returned, and \var{IPCerror} is set.
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\SeeAlso
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+\seef{shmget}, \seef{shmdt}, \seef{shmctl}
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\end{function}
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+For an example, see \seef{shmctl}.
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+
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\begin{function}{shmdt}
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\Declaration
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Function shmdt (shmaddr:pchar):boolean;
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\Description
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+\var{shmdt} detaches the shared memory at address \var{shmaddr}. This shared
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+memory block is unavailable to the current process, until it is attached
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+again by a call to \seef{shmat}.
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+
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+The function returns \var{True} if the memory block was detached
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+successfully, \var{False} otherwise.
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\Errors
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+On error, False is returned, and IPCerror is set.
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\SeeAlso
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+\seef{shmget}, \seef{shmat}, \seef{shmctl}
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\end{function}
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\begin{function}{shmctl}
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\Declaration
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Function shmctl(shmid:longint; cmd:longint; buf: pshmid\_ds): Boolean;
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\Description
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+\var{shmctl} performs various operations on the shared memory block
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+identified by identifier \var{shmid}.
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+
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+The \var{buf} parameter points to a \var{TSHMid\_ds} record. The
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+\var{cmd} parameter is used to pass which operation is to be performed.
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+It can have one of the following values :
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+\begin{description}
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+\item[IPC\_STAT] \var{shmctl} fills the \var{TSHMid\_ds} record that
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+\var{buf} points to with the available information about the shared memory
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+block.
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+\item[IPC\_SET] applies the values in the \var{ipc\_perm} record that
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+\var{buf} points to, to the shared memory block.
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+\item[IPC\_RMID] the shared memory block is destroyed (after all processes
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+to which the block is attached, have detached from it).
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+\end{description}
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+
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+If successful, the function returns \var{True}, \var{False} otherwise.
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\Errors
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+If an error occurs, the function returns \var{False}, and \var{IPCerror}
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+is set.
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\SeeAlso
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+\seef{shmget}, \seef{shmat}, \seef{shmdt}
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\end{function}
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\latex{\inputlisting{ipcex/shmtool.pp}}
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michael