gets(n) Tcl Built-In Commands gets(n)
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NAME
gets - Read a line from a channel
SYNOPSIS
gets channelId ?varName?
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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 avail-able available
able 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 insuffi-cient insufficient
cient 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.
SEE ALSO
file(n), eof(n), fblocked(n), Tcl_StandardChannels(3)
KEYWORDS
blocking, channel, end of file, end of line, line, nonblocking, read
Tcl 7.5 gets(n)
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