Hi All

I was wondering if someone can enlighten me on the following behaviour with regard to a particular code snippet

Code is:

<snip>

    $line = pack ("A1170") ;
    substr ($line, 0, 135) = " " ;
    substr ($line, 136, 11) = "DATE=${mdy}" ;
    substr ($line, 147, 6) = "${mdy}" ;
    substr ($line, 153, 6) = "${hms}" ;
    substr ($line, 159, 3) = " " ;
    substr ($line, 162, 17) = " " ;
    substr ($line, 179, 8) = "G1ADP" ;
    substr ($line, 187, 3) = "$CLIENT_ID" ;
    substr ($line, 190, 507) = " " ;
    substr ($line, 508, 1) = " " ;

[download]

<snip>

Basically I deal with outputting various data in fixed width format and like the above method as it references back quite nicely to file definitions that I follow to create the output. For instance, the above is the definition for a file header

But, I've been ignoring a couple of interesting "funnies" with this way of outputting fixed widths. These being:
1) My $line should be 510 spaces long. But if I try to set A510 I get the old substr outside of string at error and for some reason I have to set it to the value of 1170 (found by trial and error).
2) If the last field is space, then I have to add in an extra output to get the file length outputted correctly. As in the above substr ($line, 508, 1) = " " ;.
Can anyone enlighten me on what's occurring? I expect it's user error :-)

Cheers, Jake (aka spudulike)

In reply to Google has failed me! Using pack and substr for fixed width file output by spudulike

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