|MSYNC(3C)||Standard C Library Functions||MSYNC(3C)|
#include <sys/mman.h> int msync(void *addr, size_t len, int flags);
The msync() function writes all modified copies of pages over the range [addr, addr + len) to the underlying hardware, or invalidates any copies so that further references to the pages will be obtained by the system from their permanent storage locations. The permanent storage for a modified MAP_SHARED mapping is the file the page is mapped to; the permanent storage for a modified MAP_PRIVATE mapping is its swap area.
The flags argument is a bit pattern built from the following values:
If flags is MS_ASYNC or MS_SYNC, the function synchronizes the file contents to match the current contents of the memory region.
If flags is MS_ASYNC, the function may return immediately once all write operations are scheduled; if flags is MS_SYNC, the function does not return until all write operations are completed.
If flags is MS_INVALIDATE, the function synchronizes the contents of the memory region to match the current file contents.
If msync() causes any write to the file, then the file's st_ctime and st_mtime fields are marked for update.
Upon successful completion, msync() returns 0; otherwise, it returns −1 and sets errno to indicate the error.
The msync() function will fail if:
The flags argument is not some combination of MS_ASYNC and MS_INVALIDATE.
The msync() function should be used by programs that require a memory object to be in a known state, for example in building transaction facilities.
Normal system activity can cause pages to be written to disk. Therefore, there are no guarantees that msync() is the only control over when pages are or are not written to disk.
See attributes(7) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|
|July 24, 2002||OmniOS|