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<!doctype html><html lang=en class=no-js> <head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><meta name=author content="Niels Lohmann"><link href="https://json.nlohmann.me/home/exceptions/" rel="canonical"><link href=../faq/ rel=prev><link href=../releases/ rel=next><link rel=icon href=../../assets/images/favicon.png><meta name=generator content="mkdocs-1.6.1, mkdocs-material-9.7.7"><title>Exceptions - JSON for Modern C++</title><link rel=stylesheet href=../../assets/stylesheets/main.ec1eaa64.min.css><link rel=stylesheet href=../../assets/stylesheets/palette.ab4e12ef.min.css><link rel="stylesheet" href="../../assets/external/fonts.googleapis.com/css.61a430c9.css"><style>:root{--md-text-font:"Roboto";--md-code-font:"JetBrains Mono"}</style><link rel=stylesheet href=../../css/custom.css><script>__md_scope=new 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direction LR
class `std::exception` {
&lt;&lt;interface&gt;&gt;
@@ -138,7 +138,8 @@ byte position of error: 8
</code></pre></div> <div class=highlight><pre><span></span><code>[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR string: invalid string: ill-formed UTF-8 byte
</code></pre></div></p> </div> <h3 id=jsonexceptionparse_error114>json.exception.parse_error.114<a class=headerlink href=#jsonexceptionparse_error114 title="Permanent link">&para;</a></h3> <p>The parsing of the corresponding <abbr title="Binary JSON">BSON</abbr> record type is not implemented (yet).</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.parse_error.114] parse error at byte 5: Unsupported BSON record type 0xFF
</code></pre></div> </div> <h3 id=jsonexceptionparse_error115>json.exception.parse_error.115<a class=headerlink href=#jsonexceptionparse_error115 title="Permanent link">&para;</a></h3> <p>A <abbr title="Universal Binary JSON">UBJSON</abbr> high-precision number could not be parsed.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing UBJSON high-precision number: invalid number text: 1A
</code></pre></div> </div> <h2 id=iterator-errors>Iterator errors<a class=headerlink href=#iterator-errors title="Permanent link">&para;</a></h2> <p>This exception is thrown if iterators passed to a library function do not match the expected semantics.</p> <p>Exceptions have ids 2xx.</p> <details class=example> <summary>Example: catch an <code>invalid_iterator</code> exception</summary> <p>The following code shows how an <code>invalid_iterator</code> exception can be caught.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
</code></pre></div> </div> <h3 id=jsonexceptionparse_error116>json.exception.parse_error.116<a class=headerlink href=#jsonexceptionparse_error116 title="Permanent link">&para;</a></h3> <p><a href=../../api/basic_json_document/load/ ><code>basic_json_document::load()</code></a> rejected an <a href=../../features/json_view/#images>image</a>: either the bytes are not one <a href=../../api/basic_json_document/save/ ><code>save()</code></a> could have written (too short, an unknown magic number or format version, or sizes that do not fit the buffer), or they are, but fail the requested <a href=../../api/basic_json_document/load/#image_check><code>image_check</code></a>.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.parse_error.116] parse error: invalid json_document image: the check failed
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>, together with <a href=../../features/json_view/#images>images</a>.</p> </div> <h2 id=iterator-errors>Iterator errors<a class=headerlink href=#iterator-errors title="Permanent link">&para;</a></h2> <p>This exception is thrown if iterators passed to a library function do not match the expected semantics.</p> <p>Exceptions have ids 2xx.</p> <details class=example> <summary>Example: catch an <code>invalid_iterator</code> exception</summary> <p>The following code shows how an <code>invalid_iterator</code> exception can be caught.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=k>using</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>json</span><span class=p>;</span>
@@ -223,7 +224,10 @@ exception id: 308
</code></pre></div></p> </div> <div class="admonition tip"> <p class=admonition-title>Tip</p> <ul> <li>Store the source file with <abbr title="Unicode Transformation Format">UTF</abbr>-8 encoding.</li> <li>Pass an error handler as last parameter to the <code>dump()</code> function to avoid this exception:<ul> <li><code>json::error_handler_t::replace</code> will replace invalid bytes sequences with <code>U+FFFD</code> </li> <li><code>json::error_handler_t::ignore</code> will silently ignore invalid byte sequences</li> <li><code>json::error_handler_t::keep</code> will copy invalid byte sequences to the output unchanged</li> </ul> </li> </ul> </div> <h3 id=jsonexceptiontype_error317>json.exception.type_error.317<a class=headerlink href=#jsonexceptiontype_error317 title="Permanent link">&para;</a></h3> <p>The dynamic type of the object cannot be represented in the requested serialization format (e.g., a raw <code>true</code> or <code>null</code> <abbr title="JavaScript Object Notation">JSON</abbr> object cannot be serialized to <abbr title="Binary JSON">BSON</abbr>)</p> <div class="admonition failure"> <p class=admonition-title>Example messages</p> <p>Serializing <code class=highlight><span class=kc>null</span></code> to <abbr title="Binary JSON">BSON</abbr>: <div class=highlight><pre><span></span><code>[json.exception.type_error.317] to serialize to BSON, top-level type must be object, but is null
</code></pre></div> Serializing <code class=highlight><span class=p>[</span><span class=mi>1</span><span class=p>,</span><span class=mi>2</span><span class=p>,</span><span class=mi>3</span><span class=p>]</span></code> to <abbr title="Binary JSON">BSON</abbr>: <div class=highlight><pre><span></span><code>[json.exception.type_error.317] to serialize to BSON, top-level type must be object, but is array
</code></pre></div></p> </div> <div class="admonition tip"> <p class=admonition-title>Tip</p> <p>Encapsulate the <abbr title="JavaScript Object Notation">JSON</abbr> value in an object. That is, instead of serializing <code class=highlight><span class=kc>true</span></code>, serialize <code class=highlight><span class=p>{</span><span class=nt>"value"</span><span class=p>:</span><span class=w> </span><span class=kc>true</span><span class=p>}</span></code></p> </div> <h3 id=jsonexceptiontype_error318>json.exception.type_error.318<a class=headerlink href=#jsonexceptiontype_error318 title="Permanent link">&para;</a></h3> <p>With <a href=../../api/macros/json_use_objects_for_enum_keyed_maps/ ><code>JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS</code></a>, a map with enum keys is stored as an object. This exception is thrown if two of its keys are converted to the same string, so one of the entries would be lost. This happens, for instance, if <a href=../../api/macros/nlohmann_json_serialize_enum/ ><code>NLOHMANN_JSON_SERIALIZE_ENUM</code></a> does not list an enumerator and it is therefore converted like the first listed one.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.type_error.318] duplicate object key 'red'
</code></pre></div> </div> <h3 id=jsonexceptiontype_error321>json.exception.type_error.321<a class=headerlink href=#jsonexceptiontype_error321 title="Permanent link">&para;</a></h3> <p>A discarded value (one created by <a href=../../api/basic_json/parse/ ><code>parse()</code></a> with a callback that returns <code>false</code> for the value, or by default-constructing a <a href=../../api/basic_json/ ><code>basic_json</code></a> with <a href=../../api/basic_json/value_t/ ><code>value_t::discarded</code></a>) was passed to a binary serialization function, either directly or nested in an array or object. There is no way to represent a discarded value in <abbr title="Concise Binary Object Representation">CBOR</abbr>, MessagePack, <abbr title="Universal Binary JSON">UBJSON</abbr>, <abbr title="Binary JData">BJData</abbr>, <abbr title="Binary JSON">BSON</abbr>, or <abbr title="Binary Object Notation 8">BON8</abbr>.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <p>Serializing <code class=highlight><span class=p>[</span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=mi>2</span><span class=p>]</span></code> to <abbr title="Concise Binary Object Representation">CBOR</abbr>, where the second element was discarded by a parser callback: <div class=highlight><pre><span></span><code>[json.exception.type_error.321] cannot serialize discarded value to CBOR
</code></pre></div> </div> <h3 id=jsonexceptiontype_error319>json.exception.type_error.319<a class=headerlink href=#jsonexceptiontype_error319 title="Permanent link">&para;</a></h3> <p><a href=../../api/basic_json_document/set/ ><code>basic_json_document::set</code></a>, <a href=../../api/basic_json_document/push_back/ ><code>basic_json_document::push_back</code></a>, and <a href=../../api/basic_json_document/insert/ ><code>basic_json_document::insert</code></a> can store any <code>basic_json</code> value except a binary one: a <code>json_document</code> has no representation for <a href=../../features/binary_values/ >binary values</a>, which only ever arise from parsing a binary format or from an explicit <a href=../../api/basic_json/binary/ ><code>json::binary</code></a> value, not from <abbr title="JavaScript Object Notation">JSON</abbr> text.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.type_error.319] cannot store a binary value in a json_document
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>, together with editable <a href=../../features/json_view/ ><code>json_document</code>s</a>.</p> </div> <h3 id=jsonexceptiontype_error320>json.exception.type_error.320<a class=headerlink href=#jsonexceptiontype_error320 title="Permanent link">&para;</a></h3> <p><a href=../../api/basic_json_document/save/ ><code>basic_json_document::save()</code></a> cannot write an <a href=../../features/json_view/#images>image</a> of a <a href=../../api/basic_json_document/is_discarded/ >discarded</a> document. <a href=../../api/basic_json_document/save/ ><code>save()</code></a> and <a href=../../api/basic_json_document/load/ ><code>load()</code></a> also throw this exception on a big-endian target, since the image format is little-endian only.</p> <div class="admonition failure"> <p class=admonition-title>Example messages</p> <p><div class=highlight><pre><span></span><code>[json.exception.type_error.320] cannot save a discarded json_document
</code></pre></div> <div class=highlight><pre><span></span><code>[json.exception.type_error.320] json_document images need a little-endian target
</code></pre></div></p> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>, together with <a href=../../features/json_view/#images>images</a>.</p> </div> <h3 id=jsonexceptiontype_error321>json.exception.type_error.321<a class=headerlink href=#jsonexceptiontype_error321 title="Permanent link">&para;</a></h3> <p>A discarded value (one created by <a href=../../api/basic_json/parse/ ><code>parse()</code></a> with a callback that returns <code>false</code> for the value, or by default-constructing a <a href=../../api/basic_json/ ><code>basic_json</code></a> with <a href=../../api/basic_json/value_t/ ><code>value_t::discarded</code></a>) was passed to a binary serialization function, either directly or nested in an array or object. There is no way to represent a discarded value in <abbr title="Concise Binary Object Representation">CBOR</abbr>, MessagePack, <abbr title="Universal Binary JSON">UBJSON</abbr>, <abbr title="Binary JData">BJData</abbr>, <abbr title="Binary JSON">BSON</abbr>, or <abbr title="Binary Object Notation 8">BON8</abbr>.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <p>Serializing <code class=highlight><span class=p>[</span><span class=mi>1</span><span class=p>,</span><span class=w> </span><span class=mi>2</span><span class=p>]</span></code> to <abbr title="Concise Binary Object Representation">CBOR</abbr>, where the second element was discarded by a parser callback: <div class=highlight><pre><span></span><code>[json.exception.type_error.321] cannot serialize discarded value to CBOR
</code></pre></div></p> </div> <h2 id=out-of-range>Out of range<a class=headerlink href=#out-of-range title="Permanent link">&para;</a></h2> <p>This exception is thrown in case a library function is called on an input parameter that exceeds the expected range, for instance, in the case of array indices or nonexisting object keys.</p> <p>Exceptions have ids 4xx.</p> <details class=example> <summary>Example: catch an <code>out_of_range</code> exception</summary> <p>The following code shows how an <code>out_of_range</code> exception can be caught.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
@@ -267,7 +271,10 @@ array index 18446744073709551616 exceeds size_type
</code></pre></div></p> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, the <abbr title="Binary JSON">BSON</abbr> length was silently truncated, and <a href=../../api/basic_json/to_bson/ ><code>to_bson</code></a> produced documents with negative length prefixes that <a href=../../api/basic_json/from_bson/ ><code>from_bson</code></a> rejected; <a href=../../api/basic_json/to_msgpack/ ><code>to_msgpack</code></a> wrote such a value without any length, producing output that could not be read back.</p> </div> <h3 id=jsonexceptionout_of_range413>json.exception.out_of_range.413<a class=headerlink href=#jsonexceptionout_of_range413 title="Permanent link">&para;</a></h3> <p>A <abbr title="JavaScript Object Notation">JSON</abbr> Patch <code>remove</code> operation cannot be applied because the target location's parent is neither an object nor an array. Per <a href="https://datatracker.ietf.org/doc/html/rfc6902"><abbr title="Request for Comments">RFC</abbr> 6902</a>, a <code>remove</code> target must reference a member of an existing object or an element of an existing array; a primitive value (string, number, boolean, etc.) or <code>null</code> has no members or elements to remove.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>cannot remove value: the JSON Patch 'remove' target's parent is of type number, but must be an object or array
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, this situation was silently ignored (the <code>remove</code> operation had no effect).</p> </div> <h3 id=jsonexceptionout_of_range414>json.exception.out_of_range.414<a class=headerlink href=#jsonexceptionout_of_range414 title="Permanent link">&para;</a></h3> <p>A <abbr title="JavaScript Object Notation">JSON</abbr> Patch <code>move</code> operation's <code>"from"</code> location is a proper prefix of its <code>"path"</code> location. Per <a href="https://datatracker.ietf.org/doc/html/rfc6902"><abbr title="Request for Comments">RFC</abbr> 6902</a> (section 4.4), a location cannot be moved into one of its own children.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>cannot move value: 'from' path '/0' is a proper prefix of 'path' '/0/0'
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, this situation could succeed with a corrupted result: for an array target, removing the "from" element before the "add" step shifted subsequent indices, so "path" silently re-resolved to a different element than intended.</p> </div> <h3 id=jsonexceptionout_of_range415>json.exception.out_of_range.415<a class=headerlink href=#jsonexceptionout_of_range415 title="Permanent link">&para;</a></h3> <p>MessagePack's ext type and <abbr title="Binary JSON">BSON</abbr>'s binary subtype are each stored in a single byte. This exception is thrown when serializing a <a href=../../api/byte_container_with_subtype/ ><code>byte_container_with_subtype</code></a> whose subtype exceeds 255.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.out_of_range.415] subtype 70000 is too large for the MessagePack ext type (max 255)
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, subtypes above 255 were silently truncated modulo 256 instead of raising an error.</p> </div> <h2 id=further-exceptions>Further exceptions<a class=headerlink href=#further-exceptions title="Permanent link">&para;</a></h2> <p>This exception is thrown in case of errors that cannot be classified with the other exception types.</p> <p>Exceptions have ids 5xx.</p> <details class=example> <summary>Example: catch an <code>other_error</code> exception</summary> <p>The following code shows how an <code>other_error</code> exception can be caught.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, subtypes above 255 were silently truncated modulo 256 instead of raising an error.</p> </div> <h3 id=jsonexceptionout_of_range416>json.exception.out_of_range.416<a class=headerlink href=#jsonexceptionout_of_range416 title="Permanent link">&para;</a></h3> <p><a href=../../api/basic_json_document/parse/ ><code>basic_json_document::parse()</code></a> and the other parsing functions of <a href=../../api/basic_json_document/ ><code>basic_json_document</code></a> index a value's position in the source text in 32 bits, so they do not support an input of 4294967280 bytes (4 GiB minus 16 bytes) or more. The same 32-bit limit applies to an <strong>editable</strong> document's own storage: <a href=../../api/basic_json_document/set/ ><code>set</code></a> and <a href=../../api/basic_json_document/push_back/ ><code>push_back</code></a> throw this exception once the strings and number tokens written by edits reach 4 GiB in total, or once more than 4294967295 arrays/objects have had an element set or appended to them. The same limit applies to an <a href=../../features/json_view/#images>image</a>: <a href=../../api/basic_json_document/save/ ><code>save()</code></a> throws it if the node count, the text, or the decoded strings it would write would individually reach 4 GiB.</p> <div class="admonition failure"> <p class=admonition-title>Example messages</p> <p><div class=highlight><pre><span></span><code>[json.exception.out_of_range.416] input of 4294967280 bytes or more is not supported by json_document
</code></pre></div> <div class=highlight><pre><span></span><code>[json.exception.out_of_range.416] edits of 4 GiB or more are not supported by json_document
</code></pre></div> <div class=highlight><pre><span></span><code>[json.exception.out_of_range.416] images of 4 GiB or more are not supported by json_document
</code></pre></div></p> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>, together with <a href=../../features/json_view/ ><code>&lt;nlohmann/json_view.hpp&gt;</code></a>. <a href=../../api/basic_json/parse/ ><code>basic_json::parse()</code></a> has no such limit.</p> </div> <h2 id=further-exceptions>Further exceptions<a class=headerlink href=#further-exceptions title="Permanent link">&para;</a></h2> <p>This exception is thrown in case of errors that cannot be classified with the other exception types.</p> <p>Exceptions have ids 5xx.</p> <details class=example> <summary>Example: catch an <code>other_error</code> exception</summary> <p>The following code shows how an <code>other_error</code> exception can be caught.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
<span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
<span class=k>using</span><span class=w> </span><span class=n>json</span><span class=w> </span><span class=o>=</span><span class=w> </span><span class=n>nlohmann</span><span class=o>::</span><span class=n>json</span><span class=p>;</span>
@@ -301,4 +308,4 @@ array index 18446744073709551616 exceeds size_type
exception id: 501
</code></pre></div> </details> <h3 id=jsonexceptionother_error501>json.exception.other_error.501<a class=headerlink href=#jsonexceptionother_error501 title="Permanent link">&para;</a></h3> <p>A <abbr title="JavaScript Object Notation">JSON</abbr> Patch operation 'test' failed. The unsuccessful operation is also printed.</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <p>Executing <code class=highlight><span class=p>{</span><span class=nt>"op"</span><span class=p>:</span><span class=s2>"test"</span><span class=p>,</span><span class=w> </span><span class=nt>"path"</span><span class=p>:</span><span class=s2>"/baz"</span><span class=p>,</span><span class=w> </span><span class=nt>"value"</span><span class=p>:</span><span class=s2>"bar"</span><span class=p>}</span></code> on <code class=highlight><span class=p>{</span><span class=nt>"baz"</span><span class=p>:</span><span class=w> </span><span class=s2>"qux"</span><span class=p>}</span></code>:</p> <div class=highlight><pre><span></span><code>[json.exception.other_error.501] unsuccessful: {"op":"test","path":"/baz","value":"bar"}
</code></pre></div> </div> <h3 id=jsonexceptionother_error502>json.exception.other_error.502<a class=headerlink href=#jsonexceptionother_error502 title="Permanent link">&para;</a></h3> <p><a href=../../api/basic_json/to_ubjson/ ><code>to_ubjson</code></a> and <a href=../../api/basic_json/to_bjdata/ ><code>to_bjdata</code></a> were called with <code>use_type = true</code> but <code>use_size = false</code>. <abbr title="Universal Binary JSON">UBJSON</abbr> requires a size marker (<code>#</code>) after a type marker (<code>$</code>).</p> <div class="admonition failure"> <p class=admonition-title>Example message</p> <div class=highlight><pre><span></span><code>[json.exception.other_error.502] use_type requires use_size = true
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, debug builds aborted on an assertion and release builds wrote a <code>$</code> marker without <code>#</code>, which <a href=../../api/basic_json/from_ubjson/ ><code>from_ubjson</code></a> then rejected.</p> </div> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 14, 2026 15:40:55 UTC">October 14, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 384 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.Line truncated
</code></pre></div> </div> <div class="admonition note"> <p class=admonition-title>Note</p> <p>This exception was added in version 3.13.0 <span class=unreleased-version title="Not part of a release yet; the latest release is 3.12.0.">unreleased</span>. Before that, debug builds aborted on an assertion and release builds wrote a <code>$</code> marker without <code>#</code>, which <a href=../../api/basic_json/from_ubjson/ ><code>from_ubjson</code></a> then rejected.</p> </div> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 21, 2026 08:21:29 UTC">October 21, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 2013-2026 Niels Lohmann </div> </div> <div class=md-social> <a href="https://github.com/nlohmann" target="_blank" rel="noopener" title="github.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 512 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M173.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6m-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3m44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9M252.8 8C114.1 8 8 113.3 8 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C436.2 457.8 504 362.9 504 252 504 113.3 391.5 8 252.8 8M105.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1m-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </a> <a href="https://www.linkedin.com/in/nielslohmann/" target="_blank" rel="noopener" title="www.linkedin.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 448 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M416 32H31.9C14.3 32 0 46.5 0 64.3v383.4C0 465.5 14.3 480 31.9 480H416c17.6 0 32-14.5 32-32.3V64.3c0-17.8-14.4-32.3-32-32.3M135.4 416H69V202.2h66.5V416zM102.2 96a38.5 38.5 0 1 1 0 77 38.5 38.5 0 1 1 0-77m282.1 320h-66.4V312c0-24.8-.5-56.7-34.5-56.7-34.6 0-39.9 27-39.9 54.9V416h-66.4V202.2h63.7v29.2h.9c8.9-16.8 30.6-34.5 62.9-34.5 67.2 0 79.7 44.3 79.7 101.9z"/></svg> </a> <a href="https://www.xing.com/profile/Niels_Lohmann" target="_blank" rel="noopener" title="www.xing.com" class="md-social__link"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 384 512"><!-- Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.Line truncated
+68
View File
@@ -455,6 +455,20 @@ Example message
[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing UBJSON high-precision number: invalid number text: 1A
```
### json.exception.parse_error.116
[`basic_json_document::load()`](https://json.nlohmann.me/api/basic_json_document/load/index.md) rejected an [image](https://json.nlohmann.me/features/json_view/#images): either the bytes are not one [`save()`](https://json.nlohmann.me/api/basic_json_document/save/index.md) could have written (too short, an unknown magic number or format version, or sizes that do not fit the buffer), or they are, but fail the requested [`image_check`](https://json.nlohmann.me/api/basic_json_document/load/#image_check).
Example message
```
[json.exception.parse_error.116] parse error: invalid json_document image: the check failed
```
Note
This exception was added in version 3.13.0 unreleased, together with [images](https://json.nlohmann.me/features/json_view/#images).
## Iterator errors
This exception is thrown if iterators passed to a library function do not match the expected semantics.
@@ -914,6 +928,38 @@ Example message
[json.exception.type_error.318] duplicate object key 'red'
```
### json.exception.type_error.319
[`basic_json_document::set`](https://json.nlohmann.me/api/basic_json_document/set/index.md), [`basic_json_document::push_back`](https://json.nlohmann.me/api/basic_json_document/push_back/index.md), and [`basic_json_document::insert`](https://json.nlohmann.me/api/basic_json_document/insert/index.md) can store any `basic_json` value except a binary one: a `json_document` has no representation for [binary values](https://json.nlohmann.me/features/binary_values/index.md), which only ever arise from parsing a binary format or from an explicit [`json::binary`](https://json.nlohmann.me/api/basic_json/binary/index.md) value, not from JSON text.
Example message
```
[json.exception.type_error.319] cannot store a binary value in a json_document
```
Note
This exception was added in version 3.13.0 unreleased, together with editable [`json_document`s](https://json.nlohmann.me/features/json_view/index.md).
### json.exception.type_error.320
[`basic_json_document::save()`](https://json.nlohmann.me/api/basic_json_document/save/index.md) cannot write an [image](https://json.nlohmann.me/features/json_view/#images) of a [discarded](https://json.nlohmann.me/api/basic_json_document/is_discarded/index.md) document. [`save()`](https://json.nlohmann.me/api/basic_json_document/save/index.md) and [`load()`](https://json.nlohmann.me/api/basic_json_document/load/index.md) also throw this exception on a big-endian target, since the image format is little-endian only.
Example messages
```
[json.exception.type_error.320] cannot save a discarded json_document
```
```
[json.exception.type_error.320] json_document images need a little-endian target
```
Note
This exception was added in version 3.13.0 unreleased, together with [images](https://json.nlohmann.me/features/json_view/#images).
### json.exception.type_error.321
A discarded value (one created by [`parse()`](https://json.nlohmann.me/api/basic_json/parse/index.md) with a callback that returns `false` for the value, or by default-constructing a [`basic_json`](https://json.nlohmann.me/api/basic_json/index.md) with [`value_t::discarded`](https://json.nlohmann.me/api/basic_json/value_t/index.md)) was passed to a binary serialization function, either directly or nested in an array or object. There is no way to represent a discarded value in CBOR, MessagePack, UBJSON, BJData, BSON, or BON8.
@@ -1166,6 +1212,28 @@ Note
This exception was added in version 3.13.0 unreleased. Before that, subtypes above 255 were silently truncated modulo 256 instead of raising an error.
### json.exception.out_of_range.416
[`basic_json_document::parse()`](https://json.nlohmann.me/api/basic_json_document/parse/index.md) and the other parsing functions of [`basic_json_document`](https://json.nlohmann.me/api/basic_json_document/index.md) index a value's position in the source text in 32 bits, so they do not support an input of 4294967280 bytes (4 GiB minus 16 bytes) or more. The same 32-bit limit applies to an **editable** document's own storage: [`set`](https://json.nlohmann.me/api/basic_json_document/set/index.md) and [`push_back`](https://json.nlohmann.me/api/basic_json_document/push_back/index.md) throw this exception once the strings and number tokens written by edits reach 4 GiB in total, or once more than 4294967295 arrays/objects have had an element set or appended to them. The same limit applies to an [image](https://json.nlohmann.me/features/json_view/#images): [`save()`](https://json.nlohmann.me/api/basic_json_document/save/index.md) throws it if the node count, the text, or the decoded strings it would write would individually reach 4 GiB.
Example messages
```
[json.exception.out_of_range.416] input of 4294967280 bytes or more is not supported by json_document
```
```
[json.exception.out_of_range.416] edits of 4 GiB or more are not supported by json_document
```
```
[json.exception.out_of_range.416] images of 4 GiB or more are not supported by json_document
```
Note
This exception was added in version 3.13.0 unreleased, together with [`<nlohmann/json_view.hpp>`](https://json.nlohmann.me/features/json_view/index.md). [`basic_json::parse()`](https://json.nlohmann.me/api/basic_json/parse/index.md) has no such limit.
## Further exceptions
This exception is thrown in case of errors that cannot be classified with the other exception types.