Write unsigned long to a json file

[Zuputmer]

Hi, i am new to jsoncpp, so please forgive my question if it sounds ridiculous. I have an unsigned long value that i need to write to a json file. But whenever i try, i encounter the following error-
error: conversion from ‘long unsigned int’ to ‘Json::Value’ is ambiguous event ["Node Values"]["Moisture"]= (num);

Any help would be greatly appreciated.

[BillyDonahue]

Example:

  Value(Int value);
  Value(UInt value);
#if defined(JSON_HAS_INT64)
  Value(Int64 value);
  Value(UInt64 value);
#endif // if defined(JSON_HAS_INT64)
  Value(double value);
  ...
  Value(bool value);

Int : int
UInt : unsigned
Int64 : int64_t
Uint64 : uint64_t

Value can be constructed from a handful of arithmetic types, not all of them.
I guess you're on a system for which unsigned long isn't one of those types.
So the compiler has conversions to try, but unfortunately there are more than one, so it refuses to choose a winner and complains about the ambiguity.

Also see discussion on PR #66.

[Zuputmer]

@BillyDonahue Thank you for your reply. I am using jsoncpp on a raspberry pi. If i wanted to write to a json file from an unsigned long variable, how would i proceed? It keeps telling me that it cannot convert from unsigned long to Json::value. If I declare a Json value and then assign my variable to that value, it still says the same thing. Any help would be greatly appreciated.

[BillyGoto]

You have to cast to Jason::UInt. RPi can be 32- or 64-bit depending on which OS you’re using, but it’s usually 32-bit Rapbian OS. So your unsigned long is 32-bit. So it is narrower than Jason::UInt64, but outranks Jason::UInt. There’s no clear choice of conversion, so you have to do it yourself. I think we should revisit this API issue though and try to accept any integral whose range is fully representable.

On Mon, Jan 21, 2019 at 11:03 PM Zuputmer ***@***.***> wrote: @BillyDonahue <https://github.com/BillyDonahue> Thank you for your reply. I am using jsoncpp on a raspberry pi. If i wanted to write to a json file from an unsigned long variable, how would i proceed? It keeps telling me that it cannot convert from unsigned long to Json::value. If I declare a Json value and then assign my variable to that value, it still says the same thing. Any help would be greatly appreciated. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#879 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHFzPFAA_q2wQZQz0FY3BDBG24Zv4T69ks5vFo2WgaJpZM4aKjjx> .

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