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diff --git a/man-pages-posix-2003/man3p/msync.3p b/man-pages-posix-2003/man3p/msync.3p new file mode 100644 index 0000000..f00eb91 --- /dev/null +++ b/man-pages-posix-2003/man3p/msync.3p @@ -0,0 +1,144 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "MSYNC" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" msync +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.SH NAME +msync \- synchronize memory with physical storage +.SH SYNOPSIS +.LP +\fB#include <sys/mman.h> +.br +.sp +int msync(void *\fP\fIaddr\fP\fB, size_t\fP \fIlen\fP\fB, int\fP \fIflags\fP\fB); +\fP +\fB +.br +\fP +.SH DESCRIPTION +.LP +The \fImsync\fP() function shall write all modified data to permanent +storage locations, if any, in those whole pages +containing any part of the address space of the process starting at +address \fIaddr\fP and continuing for \fIlen\fP bytes. If no +such storage exists, \fImsync\fP() need not have any effect. If requested, +the \fImsync\fP() function shall then invalidate +cached copies of data. +.LP +The implementation shall require that \fIaddr\fP be a multiple of +the page size as returned by \fIsysconf\fP(). +.LP +For mappings to files, the \fImsync\fP() function shall ensure that +all write operations are completed as defined for +synchronized I/O data integrity completion. It is unspecified whether +the implementation also writes out other file attributes. +When the \fImsync\fP() function is called on MAP_PRIVATE mappings, +any modified data shall not be written to the underlying object +and shall not cause such data to be made visible to other processes. +It is unspecified whether data in MAP_PRIVATE mappings has any +permanent storage locations. The effect of \fImsync\fP() on a +shared memory object or a typed memory object is unspecified. +The behavior of this function is unspecified if the mapping was not +established by a call to \fImmap\fP(). +.LP +The \fIflags\fP argument is constructed from the bitwise-inclusive +OR of one or more of the following flags defined in the \fI<sys/mman.h>\fP +header: +.TS C +center; l2 l. +\fBSymbolic Constant\fP \fBDescription\fP +MS_ASYNC Perform asynchronous writes. +MS_SYNC Perform synchronous writes. +MS_INVALIDATE Invalidate cached data. +.TE +.LP +When MS_ASYNC is specified, \fImsync\fP() shall return immediately +once all the write operations are initiated or queued for +servicing; when MS_SYNC is specified, \fImsync\fP() shall not return +until all write operations are completed as defined for +synchronized I/O data integrity completion. Either MS_ASYNC or MS_SYNC +is specified, but not both. +.LP +When MS_INVALIDATE is specified, \fImsync\fP() shall invalidate all +cached copies of mapped data that are inconsistent with the +permanent storage locations such that subsequent references shall +obtain data that was consistent with the permanent storage +locations sometime between the call to \fImsync\fP() and the first +subsequent memory reference to the data. +.LP +If \fImsync\fP() causes any write to a file, the file's \fIst_ctime\fP +and \fIst_mtime\fP fields shall be marked for +update. +.SH RETURN VALUE +.LP +Upon successful completion, \fImsync\fP() shall return 0; otherwise, +it shall return -1 and set \fIerrno\fP to indicate the +error. +.SH ERRORS +.LP +The \fImsync\fP() function shall fail if: +.TP 7 +.B EBUSY +Some or all of the addresses in the range starting at \fIaddr\fP and +continuing for \fIlen\fP bytes are locked, and +MS_INVALIDATE is specified. +.TP 7 +.B EINVAL +The value of \fIflags\fP is invalid. +.TP 7 +.B EINVAL +The value of \fIaddr\fP is not a multiple of the page size {PAGESIZE}. +.TP 7 +.B ENOMEM +The addresses in the range starting at \fIaddr\fP and continuing for +\fIlen\fP bytes are outside the range allowed for the +address space of a process or specify one or more pages that are not +mapped. +.sp +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +The \fImsync\fP() function is only supported if the Memory Mapped +Files option and the Synchronized Input and Output option are +supported, and thus need not be available on all implementations. +.LP +The \fImsync\fP() function should be used by programs that require +a memory object to be in a known state; for example, in +building transaction facilities. +.LP +Normal system activity can cause pages to be written to disk. Therefore, +there are no guarantees that \fImsync\fP() is the only +control over when pages are or are not written to disk. +.SH RATIONALE +.LP +The \fImsync\fP() function writes out data in a mapped region to the +permanent storage for the underlying object. The call to +\fImsync\fP() ensures data integrity of the file. +.LP +After the data is written out, any cached data may be invalidated +if the MS_INVALIDATE flag was specified. This is useful on +systems that do not support read/write consistency. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fImmap\fP(), \fIsysconf\fP(), the Base Definitions volume of +IEEE\ Std\ 1003.1-2001, \fI<sys/mman.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . |