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<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Hi Even,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">thanks for your answer.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">ok with </span>/vsistdout/<span lang="EN-US" style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">I’m sure trying to finish the job. I’ve been documenting that, going through actions errors. But I’m not trying to incorporate anything new but only trying to let it clean from doubts I have from
the beginning and I left for later. Now is this later :)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Tests in windows are resisting to be passed because there are some problems with python and windows (I’m new al python) but I hope I can confront them from Monday.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Soon I’ll create the mentioned feature branch and I’ll put all modifications there and I’ll pool request.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">I’m willing to do that!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Have a nice weekend<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="ES" style="mso-fareast-language:CA">De:</span></b><span lang="ES" style="mso-fareast-language:CA"> Even Rouault <even.rouault@spatialys.com>
<br>
<b>Enviado el:</b> divendres, 23 de febrer de 2024 16:50<br>
<b>Para:</b> Abel Pau <a.pau@creaf.uab.cat>; gdal-dev@lists.osgeo.org<br>
<b>Asunto:</b> Re: [gdal-dev] the /vsistdout mistery and the Update question<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p>Abel,<o:p></o:p></p>
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<p class="MsoNormal">Le 23/02/2024 à 10:34, Abel Pau via gdal-dev a écrit :<o:p></o:p></p>
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<p class="MsoNormal"><span lang="ES">Hi,</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">after reading </span><span lang="ES"><a href="https://gdal.org/user/virtual_file_systems.html#vsistdout-standard-output-streaming"><span lang="EN-US">https://gdal.org/user/virtual_file_systems.html#vsistdout-standard-output-streaming</span></a>
</span><span lang="EN-US">I have to say I don’t understand what it means.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">I which cases it’s used? Some example to consider?</span><o:p></o:p></p>
</blockquote>
<p>/vsistdout/ also makes sense for formats that can be streamed in writing, that is you can generate the content as data flows in the driver and don't have to seek back to edit something in the header. So only a small subset of formats/drivers can natively
support that. The canonical example is a CSV file. So I'd say don't worry about that use case for your driver.<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">On the other hand, I am confused about the Update concept.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">My driver is capable of creating from zero a layer from other formats.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US">But I haven’t programmed the capacity to insert a feature in a pre-existent layer (I cannot simply add at the end of the file because de format description is a little more complicated).</span><o:p></o:p></p>
</blockquote>
<p>Same thing as above. A lot of drivers can only create + add features in the newly features, but can't (at least easily) edit or append to an existing file. So just return nullptr when Open() is called with the update flag with a CPLError() message.<o:p></o:p></p>
<p>Something like<o:p></o:p></p>
<p> if (poDS != nullptr && poOpenInfo->eAccess == GA_Update)<br>
{<br>
CPLError(CE_Failure, CPLE_OpenFailed,<br>
"SDTS Driver doesn't support update.");<br>
delete poDS;<br>
poDS = nullptr;<br>
}<o:p></o:p></p>
<p>You have been in a "development black hole" for a long time now, so I'd suggest you limit the functionality to what you've already implemented, and make it in good shape for review. The more code, the harder & longer effort for reviewers. You can always
add new functionality in follow-up pull requests once a base has already been integrated.<o:p></o:p></p>
<p>Even<o:p></o:p></p>
<p>-- <o:p></o:p></p>
<pre><a href="http://www.spatialys.com">http://www.spatialys.com</a><o:p></o:p></pre>
<pre>My software is free, but my time generally not.<o:p></o:p></pre>
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