tell - Return current access position for an open channel
tell channelId
tell(1t) Tcl Built-In Commands tell(1t) ______________________________________________________________________________ NAME tell - Return current access position for an open channel SYNOPSIS tell channelId ______________________________________________________________________________ DESCRIPTION Returns an integer string giving the current access position in chan- nelId. This value returned is a byte offset that can be passed to seek in order to set the channel to a particular position. Note that this value is in terms of bytes, not characters like read. The value returned is -1 for channels that do not support seeking. ChannelId must be an identifier for an open channel such as a Tcl stan- dard channel (stdin, stdout, or stderr), the return value from an invo- cation of open or socket, or the result of a channel creation command provided by a Tcl extension. EXAMPLE Read a line from a file channel only if it starts with foobar: # Save the offset in case we need to undo the read... set offset [tell $chan] if {[read $chan 6] eq "foobar"} { gets $chan line } else { set line {} # Undo the read... seek $chan $offset } ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+------------------+ |Availability | runtime/tcl-8 | +---------------+------------------+ |Stability | Uncommitted | +---------------+------------------+ SEE ALSO file(n), open(n), close(n), gets(n), seek(n), Tcl_StandardChannels(3) KEYWORDS access position, channel, seeking NOTES Source code for open source software components in Oracle Solaris can be found at https://www.oracle.com/downloads/opensource/solaris-source- code-downloads.html. This software was built from source available at https://github.com/oracle/solaris-userland. The original community source was downloaded from http://prdownloads.sourceforge.net/tcl/tcl- core8.6.7-src.tar.gz. Further information about this software can be found on the open source community website at https://www.tcl.tk/. Tcl 8.1 tell(1t)