40 lines
2.3 KiB
HTML
40 lines
2.3 KiB
HTML
<HTML><HEAD><TITLE>Tcl Built-In Commands - gets manual page</TITLE></HEAD><BODY>
|
|
<H3><A NAME="M2">NAME</A></H3>
|
|
gets - Read a line from a channel
|
|
<H3><A NAME="M3">SYNOPSIS</A></H3>
|
|
<B>gets </B><I>channelId</I> ?<I>varName</I>?<BR>
|
|
<H3><A NAME="M4">DESCRIPTION</A></H3>
|
|
This command reads the next line from <I>channelId</I>, returns everything
|
|
in the line up to (but not including) the end-of-line character(s), and
|
|
discards the end-of-line character(s).
|
|
If <I>varName</I> is omitted the line is returned as the result of the
|
|
command.
|
|
If <I>varName</I> is specified then the line is placed in the variable by
|
|
that name and the return value is a count of the number of characters
|
|
returned.
|
|
<P>
|
|
If end of file occurs while scanning for an end of
|
|
line, the command returns whatever input is available up to the end of file.
|
|
If <I>channelId</I> is in nonblocking mode and there is not a full
|
|
line of input available, the command returns an empty string and
|
|
does not consume any input.
|
|
If <I>varName</I> is specified and an empty string is returned in
|
|
<I>varName</I> because of end-of-file or because of insufficient
|
|
data in nonblocking mode, then the return count is -1.
|
|
Note that if <I>varName</I> is not specified then the end-of-file
|
|
and no-full-line-available cases can
|
|
produce the same results as if there were an input line consisting
|
|
only of the end-of-line character(s).
|
|
The <B><A HREF="../TkCmd/eof.htm">eof</A></B> and <B><A HREF="../TkCmd/fblocked.htm">fblocked</A></B> commands can be used to distinguish
|
|
these three cases.
|
|
|
|
<H3><A NAME="M5">SEE ALSO</A></H3>
|
|
<B><A HREF="../TkCmd/file.htm">file</A></B>, <B><A HREF="../TkCmd/eof.htm">eof</A></B>, <B><A HREF="../TkCmd/fblocked.htm">fblocked</A></B>
|
|
<H3><A NAME="M6">KEYWORDS</A></H3>
|
|
<A href="../Keywords/B.htm#blocking">blocking</A>, <A href="../Keywords/C.htm#channel">channel</A>, <A href="../Keywords/E.htm#end of file">end of file</A>, <A href="../Keywords/E.htm#end of line">end of line</A>, <A href="../Keywords/L.htm#line">line</A>, <A href="../Keywords/N.htm#nonblocking">nonblocking</A>, <A href="../Keywords/R.htm#read">read</A>
|
|
<HR><PRE>
|
|
<A HREF="../copyright.htm">Copyright</A> © 1993 The Regents of the University of California.
|
|
<A HREF="../copyright.htm">Copyright</A> © 1994-1996 Sun Microsystems, Inc.
|
|
<A HREF="../copyright.htm">Copyright</A> © 1995-1997 Roger E. Critchlow Jr.</PRE>
|
|
</BODY></HTML>
|