mirror of
https://github.com/0intro/wmii
synced 2024-11-29 17:13:11 +03:00
372 lines
6.7 KiB
Groff
372 lines
6.7 KiB
Groff
.deEX
|
|
.ift .ft5
|
|
.nf
|
|
..
|
|
.deEE
|
|
.ft1
|
|
.fi
|
|
..
|
|
.TH BIO 3
|
|
.SH NAME
|
|
Bopen, Bfdopen, Binit, Binits, Brdline, Brdstr, Bgetc, Bgetrune, Bgetd, Bungetc, Bungetrune, Bread, Bseek, Boffset, Bfildes, Blinelen, Bputc, Bputrune, Bprint, Bvprint, Bwrite, Bflush, Bterm, Bbuffered \- buffered input/output
|
|
.SH SYNOPSIS
|
|
.ta \w'\fLBiobuf* 'u
|
|
.B #include <utf.h>
|
|
.br
|
|
.B #include <fmt.h>
|
|
.br
|
|
.B #include <bio.h>
|
|
.PP
|
|
.B
|
|
Biobuf* Bopen(char *file, int mode)
|
|
.PP
|
|
.B
|
|
Biobuf* Bfdopen(int fd, int mode)
|
|
.PP
|
|
.B
|
|
int Binit(Biobuf *bp, int fd, int mode)
|
|
.PP
|
|
.B
|
|
int Binits(Biobufhdr *bp, int fd, int mode, uchar *buf, int size)
|
|
.PP
|
|
.B
|
|
int Bterm(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
int Bprint(Biobufhdr *bp, char *format, ...)
|
|
.PP
|
|
.B
|
|
int Bvprint(Biobufhdr *bp, char *format, va_list arglist);
|
|
.PP
|
|
.B
|
|
void* Brdline(Biobufhdr *bp, int delim)
|
|
.PP
|
|
.B
|
|
char* Brdstr(Biobufhdr *bp, int delim, int nulldelim)
|
|
.PP
|
|
.B
|
|
int Blinelen(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
vlong Boffset(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
int Bfildes(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
int Bgetc(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
long Bgetrune(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
int Bgetd(Biobufhdr *bp, double *d)
|
|
.PP
|
|
.B
|
|
int Bungetc(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
int Bungetrune(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
vlong Bseek(Biobufhdr *bp, vlong n, int type)
|
|
.PP
|
|
.B
|
|
int Bputc(Biobufhdr *bp, int c)
|
|
.PP
|
|
.B
|
|
int Bputrune(Biobufhdr *bp, long c)
|
|
.PP
|
|
.B
|
|
long Bread(Biobufhdr *bp, void *addr, long nbytes)
|
|
.PP
|
|
.B
|
|
long Bwrite(Biobufhdr *bp, void *addr, long nbytes)
|
|
.PP
|
|
.B
|
|
int Bflush(Biobufhdr *bp)
|
|
.PP
|
|
.B
|
|
int Bbuffered(Biobufhdr *bp)
|
|
.PP
|
|
.SH DESCRIPTION
|
|
These routines implement fast buffered I/O.
|
|
I/O on different file descriptors is independent.
|
|
.PP
|
|
.I Bopen
|
|
opens
|
|
.I file
|
|
for mode
|
|
.B O_RDONLY
|
|
or creates for mode
|
|
.BR O_WRONLY .
|
|
It calls
|
|
.IR malloc (3)
|
|
to allocate a buffer.
|
|
.PP
|
|
.I Bfdopen
|
|
allocates a buffer for the already-open file descriptor
|
|
.I fd
|
|
for mode
|
|
.B O_RDONLY
|
|
or
|
|
.BR O_WRONLY .
|
|
It calls
|
|
.IR malloc (3)
|
|
to allocate a buffer.
|
|
.PP
|
|
.I Binit
|
|
initializes a standard size buffer, type
|
|
.IR Biobuf ,
|
|
with the open file descriptor passed in
|
|
by the user.
|
|
.I Binits
|
|
initializes a non-standard size buffer, type
|
|
.IR Biobufhdr ,
|
|
with the open file descriptor,
|
|
buffer area, and buffer size passed in
|
|
by the user.
|
|
.I Biobuf
|
|
and
|
|
.I Biobufhdr
|
|
are related by the declaration:
|
|
.IP
|
|
.EX
|
|
typedef struct Biobuf Biobuf;
|
|
struct Biobuf
|
|
{
|
|
Biobufhdr;
|
|
uchar b[Bungetsize+Bsize];
|
|
};
|
|
.EE
|
|
.PP
|
|
Arguments
|
|
of types pointer to Biobuf and pointer to Biobufhdr
|
|
can be used interchangeably in the following routines.
|
|
.PP
|
|
.IR Bopen ,
|
|
.IR Binit ,
|
|
or
|
|
.I Binits
|
|
should be called before any of the
|
|
other routines on that buffer.
|
|
.I Bfildes
|
|
returns the integer file descriptor of the associated open file.
|
|
.PP
|
|
.I Bterm
|
|
flushes the buffer for
|
|
.IR bp .
|
|
If the buffer was allocated by
|
|
.IR Bopen ,
|
|
the buffer is
|
|
.I freed
|
|
and the file is closed.
|
|
.PP
|
|
.I Brdline
|
|
reads a string from the file associated with
|
|
.I bp
|
|
up to and including the first
|
|
.I delim
|
|
character.
|
|
The delimiter character at the end of the line is
|
|
not altered.
|
|
.I Brdline
|
|
returns a pointer to the start of the line or
|
|
.L 0
|
|
on end-of-file or read error.
|
|
.I Blinelen
|
|
returns the length (including the delimiter)
|
|
of the most recent string returned by
|
|
.IR Brdline .
|
|
.PP
|
|
.I Brdstr
|
|
returns a
|
|
.IR malloc (3)-allocated
|
|
buffer containing the next line of input delimited by
|
|
.IR delim ,
|
|
terminated by a NUL (0) byte.
|
|
Unlike
|
|
.IR Brdline ,
|
|
which returns when its buffer is full even if no delimiter has been found,
|
|
.I Brdstr
|
|
will return an arbitrarily long line in a single call.
|
|
If
|
|
.I nulldelim
|
|
is set, the terminal delimiter will be overwritten with a NUL.
|
|
After a successful call to
|
|
.IR Brdstr ,
|
|
the return value of
|
|
.I Blinelen
|
|
will be the length of the returned buffer, excluding the NUL.
|
|
.PP
|
|
.I Bgetc
|
|
returns the next character from
|
|
.IR bp ,
|
|
or a negative value
|
|
at end of file.
|
|
.I Bungetc
|
|
may be called immediately after
|
|
.I Bgetc
|
|
to allow the same character to be reread.
|
|
.PP
|
|
.I Bgetrune
|
|
calls
|
|
.I Bgetc
|
|
to read the bytes of the next
|
|
.SM UTF
|
|
sequence in the input stream and returns the value of the rune
|
|
represented by the sequence.
|
|
It returns a negative value
|
|
at end of file.
|
|
.I Bungetrune
|
|
may be called immediately after
|
|
.I Bgetrune
|
|
to allow the same
|
|
.SM UTF
|
|
sequence to be reread as either bytes or a rune.
|
|
.I Bungetc
|
|
and
|
|
.I Bungetrune
|
|
may back up a maximum of five bytes.
|
|
.PP
|
|
.I Bgetd
|
|
uses
|
|
.I fmtcharstod
|
|
(see
|
|
.IR fmtstrtod (3))
|
|
and
|
|
.I Bgetc
|
|
to read the formatted
|
|
floating-point number in the input stream,
|
|
skipping initial blanks and tabs.
|
|
The value is stored in
|
|
.BR *d.
|
|
.PP
|
|
.I Bread
|
|
reads
|
|
.I nbytes
|
|
of data from
|
|
.I bp
|
|
into memory starting at
|
|
.IR addr .
|
|
The number of bytes read is returned on success
|
|
and a negative value is returned if a read error occurred.
|
|
.PP
|
|
.I Bseek
|
|
applies
|
|
.IR lseek (2)
|
|
to
|
|
.IR bp .
|
|
It returns the new file offset.
|
|
.I Boffset
|
|
returns the file offset of the next character to be processed.
|
|
.PP
|
|
.I Bputc
|
|
outputs the low order 8 bits of
|
|
.I c
|
|
on
|
|
.IR bp .
|
|
If this causes a
|
|
.IR write
|
|
to occur and there is an error,
|
|
a negative value is returned.
|
|
Otherwise, a zero is returned.
|
|
.PP
|
|
.I Bputrune
|
|
calls
|
|
.I Bputc
|
|
to output the low order
|
|
16 bits of
|
|
.I c
|
|
as a rune
|
|
in
|
|
.SM UTF
|
|
format
|
|
on the output stream.
|
|
.PP
|
|
.I Bprint
|
|
is a buffered interface to
|
|
.IR print (3).
|
|
If this causes a
|
|
.IR write
|
|
to occur and there is an error,
|
|
a negative value
|
|
.RB ( Beof )
|
|
is returned.
|
|
Otherwise, the number of bytes output is returned.
|
|
.I Bvprint
|
|
does the same except it takes as argument a
|
|
.B va_list
|
|
parameter, so it can be called within a variadic function.
|
|
.PP
|
|
.I Bwrite
|
|
outputs
|
|
.I nbytes
|
|
of data starting at
|
|
.I addr
|
|
to
|
|
.IR bp .
|
|
If this causes a
|
|
.IR write
|
|
to occur and there is an error,
|
|
a negative value is returned.
|
|
Otherwise, the number of bytes written is returned.
|
|
.PP
|
|
.I Bflush
|
|
causes any buffered output associated with
|
|
.I bp
|
|
to be written.
|
|
The return is as for
|
|
.IR Bputc .
|
|
.I Bflush
|
|
is called on
|
|
exit for every buffer still open
|
|
for writing.
|
|
.PP
|
|
.I Bbuffered
|
|
returns the number of bytes in the buffer.
|
|
When reading, this is the number of bytes still available from the last
|
|
read on the file; when writing, it is the number of bytes ready to be
|
|
written.
|
|
.SH SOURCE
|
|
.B http://swtch.com/plan9port/unix
|
|
.SH SEE ALSO
|
|
.IR open (2),
|
|
.IR print (3),
|
|
.IR atexit (3),
|
|
.IR utf (7),
|
|
.SH DIAGNOSTICS
|
|
.I Bio
|
|
routines that return integers yield
|
|
.B Beof
|
|
if
|
|
.I bp
|
|
is not the descriptor of an open file.
|
|
.I Bopen
|
|
returns zero if the file cannot be opened in the given mode.
|
|
All routines set
|
|
.I errstr
|
|
on error.
|
|
.SH BUGS
|
|
.I Brdline
|
|
returns an error on strings longer than the buffer associated
|
|
with the file
|
|
and also if the end-of-file is encountered
|
|
before a delimiter.
|
|
.I Blinelen
|
|
will tell how many characters are available
|
|
in these cases.
|
|
In the case of a true end-of-file,
|
|
.I Blinelen
|
|
will return zero.
|
|
At the cost of allocating a buffer,
|
|
.I Brdstr
|
|
sidesteps these issues.
|
|
.PP
|
|
The data returned by
|
|
.I Brdline
|
|
may be overwritten by calls to any other
|
|
.I bio
|
|
routine on the same
|
|
.IR bp.
|