.\" $Id: File.3,v 1.3 2019/09/09 22:35:37 stolcke Exp $
.TH File 3 "$Date: 2019/09/09 22:35:37 $" SRILM
.SH NAME
File \-  Wrapper for stdio streams
.SH SYNOPSIS
.nf
.B "#include <File.h>"
.fi
.SH DESCRIPTION
The
.B File
class provides a simple wrapper around stdio streams for use
with C++.
It provides two kinds of convenience:
Firstly, constructors and destructors manage opening and closing of the stream.
The stream is checked for errors on closing, and the default behavior
is to exit() with an error message if a problem was found.
Secondly, the getline() method can be used for line-oriented input.
It strips comments and keeps track of input line
numbers for error reporting.
.SH "CLASS MEMBERS"
.TP
.B "File(const char *\fIname\fP, const char *\fImode\fP, int \fIexitOnError\fP = 1)"
.TP
.B "File(FILE *\fIfp\fP = 0, int \fIexitOnError\fP = 1)"
A File object can be initialized with either a filename or an existing
stdio stream.
In the first case, the file is opened according to \fImode\fP
(as if by
.BR fopen (3)).
The \fIexitOnError\fP flag determines whether I/O errors should be treated
as fatal.
.TP
.B ~File()
Destroying a File object implies closing the associated stream.
.TP
.B "char *getline()"
Returns the next line from the input, stored in a static buffer of 
up to \fBmaxLineLength\fP characters.
Empty lines and lines starting with \fB#\fP are skipped.
.TP
.B "int close()"
Closes the stream without destroying the File object.
Returns non-zero is an error condition occurs.
.TP
.B "int error()"
Returns a non-zero value if an error condition occurred on the stream.
.TP
.B "operator FILE *()"
A File object can be cast to \fBFILE *\fP to access the underlying stdio
stream.
.TP
.B "ostream &position(ostream &\fIstream\fP = cerr)"
Outputs the current line number on \fIstream\fP.
The \fIstream\fP is returned so it can be used as the left operand
of the \fB<<\fP operator.
.TP
.B "const char *name"
The filename used in creating the File object.
.TP
.B "const unsigned lineno"
The current line number as maintained by \fBgetline()\fP.
.TP
.B "int exitOnError"
When set to \fBtrue\fP this causes errors on the
stream to be handled by program termination (after printing an
error message).
.SH "SEE ALSO"
stdio(3)
.SH BUGS
Many other potentially useful functions are not provided (yet).
.SH AUTHOR
Andreas Stolcke <stolcke@icsi.berkeley.edu>
.br
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