Provided by: tcl8.4-doc_8.4.20-7_all bug


       gets - Read a line from a channel


       gets channelId ?varName?


       This command reads the next line from channelId, returns everything in the line up to (but
       not including) the end-of-line character(s), and discards the end-of-line character(s).

       ChannelId must be an identifier for an open channel such as the Tcl standard input channel │
       (stdin), the return value from an invocation of open or socket, or the result of a channel │
       creation command provided by a Tcl extension. The channel must have been opened for input.

       If varName is omitted the line is returned as the result of the command.   If  varName  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.

       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 channelId 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  varName is specified and an empty string is returned in varName
       because of end-of-file or because of insufficient  data  in  nonblocking  mode,  then  the
       return  count  is  -1.  Note that if varName 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 eof and fblocked commands can be
       used to distinguish these three cases.


       This example reads a file one line at a time and prints  it  out  with  the  current  line
       number attached to the start of each line.

              set chan [open "some.file.txt"]
              set lineNumber 0
              while {[gets $chan line] >= 0} {
                  puts "[incr lineNumber]: $line"
              close $chan


       file(3tcl), eof(3tcl), fblocked(3tcl), Tcl_StandardChannels(3tcl)


       blocking, channel, end of file, end of line, line, nonblocking, read