Getting and setting the length isn't the problem, especially as it is normally done for you. The problem is manipulating the combination of the 3 fields so that although the reality is 

malloc'd space [ | | | |s|o|m|e| |d|a|t|a| |h|e|r|e|\0]
                        ^
SV--->PVX---------------|
      CUR-------------->|..........................|   = 15
      LEN------|.....................................| = 19

[download]

which is the reverse situation to the normal thing whereby the extra space is at the end rather than the beginning; the rest of the codebase will respect these settings.

I've tried setting it up like this, but I get traps. I need to know whether I am setting it up wrong, or whether the rest of the codebase will always assume that CUR and LEN will start at the same place (ie. The same place pointed at by PVX)?

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In reply to Re^2: XS Prepending space to an SVs PV by BrowserUk
in thread XS Prepending space to an SVs PV by BrowserUk

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