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setbuf(3) [minix man page]

SETBUF(3)						     Library Functions Manual							 SETBUF(3)

NAME
setbuf, setvbuf - assign buffering to a stream SYNOPSIS
#include <stdio.h> int setbuf(FILE *stream, char *buf) int setvbuf(FILE *stream, char *buf, int type, size_t size) DESCRIPTION
The three types of buffering available are unbuffered, block buffered, and line buffered. When an output stream is unbuffered, information appears on the destination file or terminal as soon as written; when it is block buffered many characters are saved up and written as a block; when it is line buffered characters are saved up until a newline is encountered or input is read from stdin. Fflush (see fclose(3)) may be used to force the block out early. Normally all files are block buffered. A buffer is obtained from malloc(3) upon the first getc or putc(3) on the file. If the standard stream stdout refers to a terminal it is line buffered. The standard stream stderr is always unbuffered. Setbuf is used after a stream has been opened but before it is read or written. The character array buf is used instead of an automati- cally allocated buffer. If buf is the constant pointer NULL, input/output will be completely unbuffered. A manifest constant BUFSIZ tells how big an array is needed: char buf[BUFSIZ]; Setvbuf, an alternate form of setbuf, is used after a stream has been opened but before it is read or written. It has three uses, depend- ing on the value of the type argument: setvbuf(stream, buf, _IOFBF, size) Causes input/output to be fully buffered using the character array buf whose size is determined by the size argument. If buf is the constant pointer NULL, then an automatically allocated buffer will be used. setvbuf(stream, buf, _IOLBF, size) Like above, except that output will be line buffered, i.e. the buffer will be flushed when a newline is written, the buffer is full, or input is requested. setvbuf(stream, buf, _IONBF, size) Causes input/output to be completely unbuffered. Buf and size are ignored. A file can be changed between unbuffered, line buffered, or block buffered by using freopen (see fopen(3)) followed by the appropriate setvbuf call. SEE ALSO
fopen(3), getc(3), putc(3), malloc(3), fclose(3), puts(3), printf(3), fread(3). 4th Berkeley Distribution May 12, 1986 SETBUF(3)

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setbuffer(3C)						   Standard C Library Functions 					     setbuffer(3C)

NAME
setbuffer, setlinebuf - assign buffering to a stream SYNOPSIS
#include <stdio.h> void setbuffer(FILE *iop, char *abuf, size_t asize); int setlinebuf(FILE *iop); DESCRIPTION
The setbuffer() and setlinebuf() functions assign buffering to a stream. The three types of buffering available are unbuffered, block buffered, and line buffered. When an output stream is unbuffered, information appears on the destination file or terminal as soon as writ- ten; when it is block buffered, many characters are saved and written as a block; when it is line buffered, characters are saved until either a NEWLINE is encountered or input is read from stdin. The fflush(3C) function may be used to force the block out early. Normally all files are block buffered. A buffer is obtained from malloc(3C) upon the first getc(3C) or putc(3C) performed on the file. If the standard stream stdout refers to a terminal, it is line buffered. The standard stream stderr is unbuffered by default. The setbuffer() function can be used after a stream iop has been opened but before it is read or written. It uses the character array abuf whose size is determined by the asize argument instead of an automatically allocated buffer. If abuf is the null pointer, input/output will be completely unbuffered. A manifest constant BUFSIZ, defined in the <stdio.h> header, tells how large an array is needed: char buf[BUFSIZ]; The setlinebuf() function is used to change the buffering on a stream from block buffered or unbuffered to line buffered. Unlike set- buffer(), it can be used at any time that the stream iop is active. A stream can be changed from unbuffered or line buffered to block buffered by using freopen(3C). A stream can be changed from block buffered or line buffered to unbuffered by using freopen(3C) followed by setbuf(3C) with a buffer argument of NULL. RETURN VALUES
The setlinebuf() function returns no useful value. SEE ALSO
malloc(3C), fclose(3C), fopen(3C), fread(3C), getc(3C), printf(3C), putc(3C), puts(3C), setbuf(3C), setvbuf(3C) NOTES
A common source of error is allocating buffer space as an "automatic" variable in a code block, and then failing to close the stream in the same block. SunOS 5.11 13 May 1997 setbuffer(3C)
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