how can I get char* from message.getSegmentsForOutput();

[张小]

capnp::MallocMessageBuilder message;

kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = message.getSegmentsForOutput();

and I want get char* from segments how can i do ? 

[Kenton Varda]

Like this (broken into three lines with full types for illustrative purposes):

    kj::ArrayPtr<const capnp::word> segment = segments[i];

    kj::ArrayPtr<const char> chars = segment.asChars();

    const char* ptr = chars.begin();

    size_t charCount = chars.size();

-Kenton

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[张小]

when i  get the char* mem addr how can I convert char* to  kj::ArrayPtr<const capnp::word> segment ?

在 2019年9月30日星期一 UTC+8上午4:26:27，Kenton Varda写道：

Like this (broken into three lines with full types for illustrative purposes):

    kj::ArrayPtr<const capnp::word> segment = segments[i];

    kj::ArrayPtr<const char> chars = segment.asChars();

    const char* ptr = chars.begin();

    size_t charCount = chars.size();

-Kenton

On Sun, Sep 29, 2019 at 8:28 AM 张小 <7745...@qq.com> wrote:

capnp::MallocMessageBuilder message;

kj::ArrayPtr<const kj::ArrayPtr<const capnp::word>> segments = message.getSegmentsForOutput();

and I want get char* from segments how can i do ? 

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[Kenton Varda]

On Sun, Sep 29, 2019 at 9:45 PM 张小 <7745...@qq.com> wrote:

I hava do this ,how can I get the Message from char* val_buf

kj::ArrayPtr<capnp::word> capn_buf = kj::arrayPtr(reinterpret_cast<capnp::word*>(val_buf), data_file_size);

That works with the caveat that it doesn't consider alignment -- if val_buf is not word-aligned then all the reads from this buffer will be misaligned. That may or may not matter depending on your CPU architecture and performance requirements.

-Kenton

 

在 2019年9月30日星期一 UTC+8上午11:07:19，张小写道：

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