setlinebuf()

Assign line buffering to a stream

Synopsis:

#include <unix.h>

int setlinebuf( FILE *iop );

Arguments:

iop
The stream that you want to use line buffering.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The setbuffer() and setlinebuf() functions assign buffering to a stream. The types of buffering available are:

Unbuffered
Information appears on the destination file or terminal as soon as written.
Block-buffered
Many characters are saved and written as a block.
Line-buffered
Characters are saved until either a newline is encountered or input is read from stdin.

You can use fflush() to force the block out early. Normally all files are block-buffered. A buffer is obtained from malloc() when the first getc() or putc() is performed on the file. If the standard stream stdout refers to a terminal, it's line-buffered. The standard stream stderr is unbuffered by default.

You can use setlinebuf() to change the buffering on a stream from block-buffered or unbuffered to line-buffered. Unlike setbuffer(), you can call setlinebuf() at any time that the stream iop is active.

You can use freopen() . to change a stream from unbuffered or line-buffered to block buffered. To change a stream from block-buffered or line-buffered to unbuffered, call freopen(), and then call setbuf() with a buffer argument of NULL.

Returns:

No useful value.

Classification:

Unix

Safety:  
Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes

Last modified: 2013-12-23

comments powered by Disqus