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"Warn" prints faster than "print"? Race conditions question

run414
New User

Mar 4, 2009, 10:34 AM

Post #1 of 4 (345 views)

"Warn" prints faster than "print"? Race conditions question	Can't Post

I'm having some problems with race conditions in my program, as warn and print are not guaranteed to print in the order they are called.

For example, consider the part of my program shown below

Code

if(do pattern matching stuff) 
{ 
    print "Now looking at document titled $1) 
} 
 
if(do more pattern matching stuff) 
{ 
   warn "This document contains terrible, terrible things\n"; 
}

The output is always:

Quote

This document contains terrible, terrible things
Now looking at document titled Bob

This is really annoying. Does anybody have any suggestions to force the warn and print to finish in the correct order?

FishMonger
Veteran

Mar 4, 2009, 10:45 AM

Post #2 of 4 (343 views)

Re: [run414] "Warn" prints faster than "print"? Race conditions question [In reply to]	Can't Post

Code

$| = 1; 
 
if(do pattern matching stuff)  
{  
    print "Now looking at document titled $1)  
}  
  
if(do more pattern matching stuff)  
{  
   warn "This document contains terrible, terrible things\n";  
}

run414
New User

Mar 4, 2009, 11:01 AM

Post #3 of 4 (341 views)

Re: [FishMonger] "Warn" prints faster than "print"? Race conditions question [In reply to]	Can't Post

Hey, that worked. I haven't heard of the $| variable before. What does it do?

Nevermind. I found an explanation here: http://www.bjnet.edu.cn/tech/book/perl/ch17.htm#BufferingOutputTTFONTSIZEFONTTT

(This post was edited by run414 on Mar 4, 2009, 11:09 AM)

FishMonger
Veteran

Mar 4, 2009, 11:11 AM

Post #4 of 4 (337 views)

Re: [run414] "Warn" prints faster than "print"? Race conditions question [In reply to]	Can't Post

autoflush HANDLE EXPR
$OUTPUT_AUTOFLUSH
$|

http://www.perl.com/doc/manual/html/pod/perlvar.html

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