sync

Name

sync - commit buffer cache to disk

Library

libc.lib

Synopsis

#include <unistd.h>

void sync (void);

Detailed description

The sync system call forces a write of dirty (modified) buffers in the block buffer cache out to disk. The kernel keeps this information in core to reduce the number of disk I/O transfers required by the system. As information in the cache is lost after a system crash, a sync system call is issued frequently by the user process syncer (about every 30 seconds).

The fsync system call may be used to synchronize individual file descriptor attributes.

Examples

/**
 * This sample code demonstrates usage of sync system call
 *
**/
#include <unistd.h>
#include <stdio.h>
int main()
{
  sync()  ;
  printf("sync system call flused all dirty buffers 0) ;
  return 0 ;
}

Output

sync system call flused all dirty buffers

Bugs

The sync system call may return before the buffers are completely flushed.

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