Tcl Built-In Commands                                    gets(1T)





NAME
     gets - Read a line from a channel

SYNOPSIS
     gets channelId ?varName?



DESCRIPTION
     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 speci-
     fied  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.

EXAMPLE
     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



Tcl                     Last change: 7.5                        1






Tcl Built-In Commands                                    gets(1T)



SEE ALSO
     file(1T), eof(1T), fblocked(1T), TclStandardChannels(3TCL)


KEYWORDS
     blocking, channel, end of file, end of line, line, nonblock-
     ing, read

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     
       ATRIBUTE TYPE     ATRIBUTE VALUE
    
     Availability         SUNWTcl        
    
     Interface Stability  Uncommitted    
    

NOTES
     Source for Tcl is available on http:/opensolaris.org.

































Tcl                     Last change: 7.5                        2