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Annotation of researchv10dc/dist/man/v4/man3/getc.3, revision 1.1.1.1

1.1       root        1: .th GETC III 4/30/72
                      2: .sh NAME
                      3: getc  \*-  buffered input
                      4: .sh SYNOPSIS
                      5: .ft B
                      6: mov    $filename,r0
                      7: .br
                      8: jsr    r5,fopen; iobuf
                      9: .s3
                     10: fopen(filename, iobuf)
                     11: .br
                     12: char *filename;
                     13: .br
                     14: struct buf *iobuf;
                     15: .s3
                     16: jsr    r5,getc; iobuf
                     17: .br
                     18: .ft R
                     19: (character in r0)
                     20: .s3
                     21: .ft B
                     22: getc(iobuf)
                     23: .br
                     24: struct buf *iobuf;
                     25: .s3
                     26: jsr    r5,getw; iobuf
                     27: .br
                     28: .ft R
                     29: (word in r0)
                     30: .s3
                     31: [getw not available in C]
                     32: .sh DESCRIPTION
                     33: These routines provide a buffered input
                     34: facility.
                     35: .it Iobuf
                     36: is the address of a 518(10) byte buffer area whose
                     37: contents are maintained by these routines.  Its format is:
                     38: .s3
                     39: .nf
                     40: .ft B
                     41: ioptr: .=.+2           / file descriptor
                     42:        .=.+2           / characters left in buffer
                     43:        .=.+2           / ptr to next character
                     44:        .=.+512.        / the buffer
                     45: .ft R
                     46: .s3
                     47: Or in C,
                     48: .s3
                     49: .ft B
                     50:        struct buf {
                     51:                int fildes;
                     52:                int nleft;
                     53:                char *nextp;
                     54:                char buffer[512];
                     55:        };
                     56: .ft R
                     57: .s3
                     58: .fi
                     59: .it Fopen
                     60: may be called initially to open the file.  On return,
                     61: the error bit (c-bit) is set if the open failed.
                     62: If \fIfopen\fR is never called, \fIget\fR will
                     63: read from the standard
                     64: input file.
                     65: From C, the value is negative if the open failed.
                     66: .s3
                     67: .it Getc
                     68: returns the next byte from the file in r0.  The
                     69: error bit is set on end of file or a read error.
                     70: From C, the character is returned;
                     71: it is \*-1 on end-of-file or error.
                     72: .s3
                     73: \fIGetw\fR returns the next word in r0.
                     74: .it Getc
                     75: and
                     76: \fIgetw\fR
                     77: may be used alternately; there are no odd/even
                     78: problems.
                     79: \fIGetw\fR is not available from C.
                     80: .s3
                     81: .it Iobuf
                     82: must be provided by the user; it must be on a word boundary.
                     83: .s3
                     84: To reuse the same buffer for another file, it is sufficient
                     85: to close the original file and call \fIfopen\fR again.
                     86: .sh "SEE ALSO"
                     87: open(II), read(II), putc(III)
                     88: .sh DIAGNOSTICS
                     89: c-bit set on EOF or error;
                     90: .br
                     91: from C, negative return indicates error or EOF.
                     92: .sh BUGS

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