.ds Vv 1.2.14
.TH VistaIOOpenFile 3 "6 June 1994" "VistaIO Version \*(Vv"
.SH NAME
VistaIOOpenInputFile, VistaIOOpenOutputFile \- open file with error checking
.SH SYNOPSIS
.nf
.B "#include <vistaio.h>"
.PP
.B "FILE *VistaIOOpenInputFile (VistaIOStringConst \fIfilename\fP, VistaIOBoolean \fInofail\fP);"
.PP
.B "FILE *VistaIOOpenOutputFile (VistaIOStringConst \fIfilename\fP, VistaIOBoolean \fInofail\fP);"
.fi
.SH ARGUMENTS
.IP \fIfilename\fP 10n
Specifies he name of the file to be opened.
.IP \fInofail\fP
Specifies whether the routine should exit the program if the file cannot be
opened.
.SH DESCRIPTION
These routines open a file while checking for failure and recognizing the
special filename ``-'' as denoting the standard input or output stream.
.PP
If \fIfilename\fP is 
.SB NULL
or it is the string ``-'', either \fBstdin\fP or \fBstdout\fP is returned.
Otherwise, an attempt is made to open the named file for either reading or
writing, as appropriate. If the attempt is successful, the resulting file
pointer is returned.
.PP
The \fInofail\fP argument determines what happens if a file cannot be
opened. If \fInofail\fP is 
.SB FALSE
then a warning message is issued and
.SB NULL
is returned. If \fInofail\fP is
.SB TRUE
then a fatal error message is issued and the program is terminated.
.SH "RETURN VALUES"
Either routing returns a pointer to the opened \fBFILE\fP if
successful. Otherwise it returns
.SB NULL
or doesn't return at all (depending on \fInofail\fP).
.SH "SEE ALSO"
.na
.nh
.BR VistaIOIdentifyFiles (3),
.BR VistaIOReadObjects (3),
.BR VistaIOWriteObjects (3),

.ad
.hy
.SH DIAGNOSTICS
.IP "``Unable to open input/output file \fIfilename\fP.''"
.SH AUTHOR
Art Pope <pope@cs.ubc.ca>

Adaption to vistaio: Gert Wollny <gw.fossdev@gmail.com>