214 lines
3.9 KiB
Plaintext
214 lines
3.9 KiB
Plaintext
.TH FGETC 2
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.SH NAME
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fgetc, getc, getchar, fputc, putc, putchar, ungetc, fgets, gets, fputs, puts, fread, fwrite \- Stdio input and output
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <stdio.h>
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.ta \w'\fLlong 'u
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.PP
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.B
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int fgetc(FILE *f)
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.PP
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.B
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int getc(FILE *f)
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.PP
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.B
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int getchar(void)
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.PP
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.B
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int fputc(int c, FILE *f)
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.PP
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.B
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int putc(int c, FILE *f)
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.PP
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.B
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int putchar(int c)
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.PP
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.B
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int ungetc(int c, FILE *f)
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.PP
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.B
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char *fgets(char *s, int n, FILE *f)
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.PP
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.B
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char *gets(char *s)
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.PP
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.B
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int fputs(char *s, FILE *f)
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.PP
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.B
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int puts(char *s)
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.PP
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.B
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long fread(void *ptr, long itemsize, long nitems, FILE *stream)
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.PP
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.B
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long fwrite(void *ptr, long itemsize, long nitems, FILE *stream)
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.SH DESCRIPTION
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The functions described here work on open Stdio streams (see
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.IR fopen ).
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.PP
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.I Fgetc
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returns as an
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.B int
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the next
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.B unsigned
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.B char
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from input stream
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.IR f .
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If the stream is at end-of-file, the end-of-file indicator for the
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stream is set and
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.I fgetc
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returns
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.BR EOF .
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If a read error occurs, the error indicator for the stream is set and
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.I fgetc
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returns
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.BR EOF .
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.I Getc
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is like
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.I fgetc
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except that it is implemented as a macro.
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.I Getchar
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is like
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.I getc
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except that it always reads from
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.BR stdin .
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.PP
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.I Ungetc
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pushes character
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.I c
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back onto the input stream
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.BR f .
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The pushed-back character will be returned by subsequent reads in
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the reverse order of their pushing.
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A successful intervening
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.IR fseek ,
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.IR fsetpos ,
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or
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.I rewind
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on
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.I f
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discards any pushed-back characters for
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.IR f .
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One character of push-back is guaranteed.
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.I Ungetc
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returns the character pushed back (converted to
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.B unsigned
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.BR char ),
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or
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.B EOF
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if the operation fails.
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A successful call to
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.I ungetc
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clears the end-of-file indicator for the stream.
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The file position indicator for the stream after reading or discarding
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all pushed-back characters is the same as it was before the
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characters were pushed back.
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.PP
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.I Fputc
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writes character
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.I c
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(converted to
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.B unsigned
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.BR char )
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to output stream
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.IR f
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at the position indicated by the position indicator for the stream
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and advances the indicator appropriately.
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If the file cannot support positioning requests, or if the stream was
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opened with append mode, the character is appended to the output stream.
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.I Fputc
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returns the character written or
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.B EOF
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if there was a write error.
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.I Putc
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is like
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.IR fputc
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but is implemented as a macro.
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.I Putchar
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is like
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.I putc
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except that it always writes to
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.BR stdout .
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.PP
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All other input takes place as if characters were read by successive
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calls to
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.I fgetc
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and all other output takes place as if characters were written by
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successive calls to
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.IR fputc .
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.PP
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.I Fgets
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reads up to and including the next newline, but not past end-of-file
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or more than
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.IR n -1
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characters, from stream
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.I f
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into array
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.IR s .
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A null character is written immediately after the last character read
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into the array (if any characters are read at all).
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.I Fgets
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returns
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.I s
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if successful, otherwise a null pointer.
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.I Gets
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is similar to
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.IR fgets
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except that it always reads from
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.B stdin
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and it discards the terminating newline, if any.
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.I Gets
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does not check for overflow of the receiving array, so its use is deprecated.
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.PP
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.I Fputs
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writes the string
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.I s
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to stream
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.IR f ,
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returning
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.B EOF
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if a write error occurred, otherwise a nonnegative value.
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The terminating null character is not written.
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.I Puts
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is the same, writing to
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.BR stdout .
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.PP
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.I Fread
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reads from the named input
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.IR stream
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at most
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.I nitems
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of data of size
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.I itemsize
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and the type of
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.I *ptr
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into a block beginning at
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.IR ptr .
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It returns the number of items actually read.
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.PP
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.I Fwrite
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appends to the named output
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.I stream
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at most
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.I nitems
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of data of size
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.I itemsize
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and the type of
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.I *ptr
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from a block beginning at
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.IR ptr .
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It returns the number of items actually written.
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.SH SOURCE
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.B /sys/src/libstdio
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.SH "SEE ALSO"
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.IR read (2),
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.IR fopen (2),
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.IR bio (2)
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.SH BUGS
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Stdio does not handle
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.SM UTF
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or runes; use Bio instead.
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