◄Up► ◄Contents► ◄Index► ◄Back► ─────Run-Time Library─────────────────────────────────────────────────────── Constant: "c", "n" Include: <stdio.h> Context: _fdopen, fopen Summary: Specifies whether the buffer associated with the open file is flushed to the operating system's buffers or to disk. The mode is included in the string specifying the type of access ("r", "w", "a", "r+", "w+", "a+"). The modes are described below. Mode Meaning "c" Write the unwritten contents of the specified buffer to disk. This commit-to-disk functionality only occurs at explicit calls to either the fflush or the _flushall function. This mode is useful when dealing with sensitive data. For example, if your program dies after a call to fflush or _flushall, you can be sure that your data reached the operating system's buffers. However, unless a file is opened with the "c" option, the data might never make it to disk if the operating system also dies. "n" Write the unwritten contents of the specified buffer to the operating system's buffers. The operating system can cache data and then determine an optimal time to write to disk. Under many conditions, this behavior makes for efficient program behavior. However, if the retention of data is critical (such as bank transactions or airline ticket information) consider using the "c" option. The "n" mode is the default. NOTE: The "c" and "n" options are not part of the ANSI standard for fopen, but are Microsoft extensions and should not be used where ANSI portability is desired. See: ◄COMMODE.OBJ► -♦-