icc while 问题

wenjian07

本人初学tcl，遇到问题请大神帮忙解答

脚本功能：使用while 循环形势复制一个文件

#
set sf_input [ open in.txt r ]
set sf_output [ open out.txt w ]

while { [ gets $sf_input line ] } {
puts $sf_output $line
}

close $sf_input
close $sf_output

执行这个脚本时，while 循环不能退出，好像是进入了死循环，麻烦帮忙分析下那里出问题了

sjtusonic

回复 1# wenjian07


   
while {[gets $chan line] >= 0} {
    puts "[incr lineNumber]: $line"
}
while条件中加上 >=0 即可

wenjian07

回复 2# sjtusonic


    为什么我写的不行呢，input文件中没有空白行，gets第一次执行应该得到的应该就是>0的数阿

sjtusonic

回复 3# wenjian07


    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 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 varName is specified and an empty string is returned in varName because of end-of-file or because of insufficient data in non-blocking 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.


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