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author | William Joye <wjoye@cfa.harvard.edu> | 2018-12-25 19:56:49 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2018-12-25 19:56:49 (GMT) |
commit | d5a4b3667e9d26b9c13905ccb51021d13ce87c58 (patch) | |
tree | fc0f3692516c8c3e8090df20223d342a1b64df93 /tcl8.6/doc/gets.n | |
parent | ff51550ee89b473c63df78de6b2a413f21105687 (diff) | |
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update tcl/tk
Diffstat (limited to 'tcl8.6/doc/gets.n')
-rw-r--r-- | tcl8.6/doc/gets.n | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/tcl8.6/doc/gets.n b/tcl8.6/doc/gets.n new file mode 100644 index 0000000..0150f29 --- /dev/null +++ b/tcl8.6/doc/gets.n @@ -0,0 +1,71 @@ +'\" +'\" Copyright (c) 1993 The Regents of the University of California. +'\" Copyright (c) 1994-1996 Sun Microsystems, Inc. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +.TH gets n 7.5 Tcl "Tcl Built-In Commands" +.so man.macros +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +gets \- Read a line from a channel +.SH SYNOPSIS +\fBgets \fIchannelId\fR ?\fIvarName\fR? +.BE + +.SH DESCRIPTION +.PP +This command reads the next line from \fIchannelId\fR, returns everything +in the line up to (but not including) the end-of-line character(s), and +discards the end-of-line character(s). +.PP +\fIChannelId\fR must be an identifier for an open channel such as the +Tcl standard input channel (\fBstdin\fR), the return value from an +invocation of \fBopen\fR or \fBsocket\fR, or the result of a channel +creation command provided by a Tcl extension. The channel must have +been opened for input. +.PP +If \fIvarName\fR is omitted the line is returned as the result of the +command. +If \fIvarName\fR 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. +.PP +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 \fIchannelId\fR is in non-blocking mode and there is not a full +line of input available, the command returns an empty string and +does not consume any input. +If \fIvarName\fR is specified and an empty string is returned in +\fIvarName\fR because of end-of-file or because of insufficient +data in non-blocking mode, then the return count is -1. +Note that if \fIvarName\fR 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 \fBeof\fR and \fBfblocked\fR commands can be used to distinguish +these three cases. +.SH "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. +.PP +.CS +set chan [open "some.file.txt"] +set lineNumber 0 +while {[\fBgets\fR $chan line] >= 0} { + puts "[incr lineNumber]: $line" +} +close $chan +.CE + +.SH "SEE ALSO" +file(n), eof(n), fblocked(n), Tcl_StandardChannels(3) + +.SH KEYWORDS +blocking, channel, end of file, end of line, line, non-blocking, read +'\" Local Variables: +'\" mode: nroff +'\" fill-column: 78 +'\" End: |