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Can I reuse 'sub' builder instances generated from a flatbuffers::FlatBufferBuilder after calling builder.Clear()? What is the effect of builder.Clear() on sub-builders?

Having generated a flatbuffers schema such as the following:

table FB_mytable1{
myshort::ushort = 0;
}
table FB_table2{
nestedTable1::FB_mytable1;
nestedTable1::FB_mytable1;
}
root_type FB_table2;

If I reset the builder using builder.clear(), my instantiation of 'flatbuffers::FlatBufferBuilder', will this allow me to generate new serial data without calling a reset function or renewing any of the individual table serialisers, such as my instantiation of FB_mytable1Builder myFB_mytable1Builder(builder)? Or do I need to ensure that the individual builder objects have a scope that means they are not reused?

user3235290
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1 Answers1

3

clear() resets a FlatBufferBuilder as if just constructed, and any of the table builder instances should not be reused across multiple buffers or even multiple tables.

See, a FlatBufferBuilder is a somewhat heavyweight structure (since it owns a buffer), so it makes sense to reuse it when you can. The table builders however are super lightweight, so should just be a local variable used for construction of a single table, you can't reuse them.

Aardappel
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  • Thank you for taking the time to understand my question. I will update it to better describe the question that you have answered for me, which was indeed what I needed to know. – user3235290 Jan 07 '17 at 17:30
  • Ok, removed "Not entirely sure what you're asking" from my answer :) – Aardappel Jan 07 '17 at 18:10