diff options
Diffstat (limited to 'doc/gets.n')
| -rw-r--r-- | doc/gets.n | 35 |
1 files changed, 28 insertions, 7 deletions
@@ -5,10 +5,8 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: gets.n,v 1.2 1998/09/14 18:39:52 stanton Exp $ -'\" -.so man.macros .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 @@ -22,6 +20,13 @@ gets \- Read a line from a channel 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 @@ -30,21 +35,37 @@ 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 nonblocking mode and there is not a full +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 nonblocking mode, then the return count is -1. +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" -eof(n), fblocked(n) +file(n), eof(n), fblocked(n), Tcl_StandardChannels(3) .SH KEYWORDS -blocking, channel, end of file, end of line, line, nonblocking, read +blocking, channel, end of file, end of line, line, non-blocking, read +'\" Local Variables: +'\" mode: nroff +'\" fill-column: 78 +'\" End: |