setbuf---specify full buffering for a file or stream
#include <stdio.h> void setbuf(FILE *fp, char *buf);
setbuf specifies that output to the file or stream identified by fp
should be fully buffered. All output for this file will go to a
buffer (of size
BUFSIZ, specified in `
stdio.h'). Output will
be passed on to the host system only when the buffer is full, or when
an input operation intervenes.
You may, if you wish, supply your own buffer by passing a pointer to
it as the argument buf. It must have size
BUFSIZ. You can
NULL as the value of buf, to signal that the
setbuf function is to allocate the buffer.
You may only use
setbuf before performing any file operation other
than opening the file.
If you supply a non-null buf, you must ensure that the associated storage continues to be available until you close the stream identified by fp.
setbuf does not return a result.
Both ANSI C and the System V Interface Definition (Issue 2) require
setbuf. However, they differ on the meaning of a
pointer: the SVID issue 2 specification says that a
pointer requests unbuffered output. For maximum portability, avoid
NULL buffer pointers.
Supporting OS subroutines required:
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