gets(n) Tcl Built-In Commands gets(n)
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 con-
sisting only of the end-of-line character(s). The eof and fblocked commands can be used
to distinguish these three cases.
file(n), eof(n), fblocked(n), Tcl_StandardChannels(3)
blocking, channel, end of file, end of line, line, nonblocking, read
Tcl 7.5 gets(n)