[#BloombergLP-bdls-FilesystemUtil-sync] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdls.adoc[bdls]::xref:BloombergLP/bdls/FilesystemUtil.adoc[FilesystemUtil]::sync :relfileprefix: ../../../ :mrdocs: Synchronize the contents of the specified `numBytes` of mapped memory beginning at the specified `address` with the underlying file on disk. If the specified `syncFlag` is true, block until all writes to nonvolatile media have actually completed, otherwise, return once they have been scheduled. Return 0 on success, and a non‐zero value otherwise. The behavior is undefined unless `address` is aligned on a page boundary, `numBytes` is a multiple of `pageSize()`, and `0 <= numBytes`. == Synopsis Declared in `<bdls_filesystemutil.h>` [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- static int sync( char* address, std::size_t numBytes, bool syncFlag); ---- [.small]#Created with https://www.mrdocs.com[MrDocs]#