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diff --git a/man-pages-posix-2013/man3p/msync.3p b/man-pages-posix-2013/man3p/msync.3p new file mode 100644 index 0000000..833a4ba --- /dev/null +++ b/man-pages-posix-2013/man3p/msync.3p @@ -0,0 +1,191 @@ +'\" et +.TH MSYNC "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual" +.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 +\(em synchronize memory with physical storage +.SH SYNOPSIS +.LP +.nf +#include <sys/mman.h> +.P +int msync(void *\fIaddr\fP, size_t \fIlen\fP, int \fIflags\fP); +.fi +.SH DESCRIPTION +The +\fImsync\fR() +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 +.IR addr +and continuing for +.IR len +bytes. If no such storage exists, +\fImsync\fR() +need not have any effect. If requested, the +\fImsync\fR() +function shall then invalidate cached copies of data. +.P +The implementation may require that +.IR addr +be a multiple of the page size as returned by +\fIsysconf\fR(). +.P +For mappings to files, the +\fImsync\fR() +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\fR() +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\fR() +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\fR(). +.P +The +.IR flags +argument is constructed from the bitwise-inclusive OR of one or more of +the following flags defined in the +.IR <sys/mman.h> +header: +.TS +center box tab(!); +cB | cB +lw(1.5i) | lw(2i). +Symbolic Constant!Description +_ +MS_ASYNC!Perform asynchronous writes. +MS_SYNC!Perform synchronous writes. +MS_INVALIDATE!Invalidate cached data. +.TE +.P +When MS_ASYNC is specified, +\fImsync\fR() +shall return immediately once all the write operations are initiated or +queued for servicing; when MS_SYNC is specified, +\fImsync\fR() +shall not return until all write operations are completed as defined for +synchronized I/O data integrity completion. Either MS_ASYNC or MS_SYNC +shall be specified, but not both. +.P +When MS_INVALIDATE is specified, +\fImsync\fR() +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\fR() +and the first subsequent memory reference to the data. +.P +If +\fImsync\fR() +causes any write to a file, the file's last data modification and +last file status change timestamps shall be marked for update. +.SH "RETURN VALUE" +Upon successful completion, +\fImsync\fR() +shall return 0; otherwise, it shall return \(mi1 and set +.IR errno +to indicate the error. +.SH ERRORS +The +\fImsync\fR() +function shall fail if: +.TP +.BR EBUSY +Some or all of the addresses in the range starting at +.IR addr +and continuing for +.IR len +bytes are locked, and MS_INVALIDATE is specified. +.TP +.BR EINVAL +The value of +.IR flags +is invalid. +.TP +.BR ENOMEM +The addresses in the range starting at +.IR addr +and continuing for +.IR len +bytes are outside the range allowed for the address space of a process +or specify one or more pages that are not mapped. +.P +The +\fImsync\fR() +function may fail if: +.TP +.BR EINVAL +The value of +.IR addr +is not a multiple of the page size as returned by +\fIsysconf\fR(). +.LP +.IR "The following sections are informative." +.SH EXAMPLES +None. +.SH "APPLICATION USAGE" +The +\fImsync\fR() +function is only supported if the Synchronized Input and Output +option is supported, and thus need not be available on all implementations. +.P +The +\fImsync\fR() +function should be used by programs that require a memory object to be +in a known state; for example, in building transaction facilities. +.P +Normal system activity can cause pages to be written to disk. +Therefore, there are no guarantees that +\fImsync\fR() +is the only control over when pages are or are not written to disk. +.SH RATIONALE +The +\fImsync\fR() +function writes out data in a mapped region to the permanent +storage for the underlying object. The call to +\fImsync\fR() +ensures data integrity of the file. +.P +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" +None. +.SH "SEE ALSO" +.IR "\fImmap\fR\^(\|)", +.IR "\fIsysconf\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2008, +.IR "\fB<sys_mman.h>\fP" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, Copyright (C) 2013 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html . + +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |