nlohmann::basic_json::parse_error

class parse_error : public exception;

The library throws this exception when a parse error occurs. Parse errors can occur during the deserialization of JSON text, BSON, CBOR, MessagePack, UBJSON, as well as when using JSON Patch.

Member byte holds the byte index of the last read character in the input file (see note below).

Exceptions have ids 1xx (see list of parse errors).

Member functions

• what - returns explanatory string

Member variables

• id - the id of the exception
• byte - byte index of the parse error

Notes

For an input with n bytes, 1 is the index of the first character and n+1 is the index of the terminating null byte or the end of file. This also holds true when reading a byte vector for binary formats.

Examples

Example

The following code shows how a parse_error exception can be caught.

#include <iostream>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

int main()
{
    try
    {
        // parsing input with a syntax error
        json::parse("[1,2,3,]");
    }
    catch (const json::parse_error& e)
    {
        // output exception information
        std::cout << "message: " << e.what() << '\n'
                  << "exception id: " << e.id << '\n'
                  << "byte position of error: " << e.byte << std::endl;
    }
}

Output:

message: [json.exception.parse_error.101] parse error at line 1, column 8: syntax error while parsing value - unexpected ']'; expected '[', '{', or a literal
exception id: 101
byte position of error: 8

See also

• List of parse errors
• invalid_iterator for exceptions indicating errors with iterators
• type_error for exceptions indicating executing a member function with a wrong type
• out_of_range for exceptions indicating access out of the defined range
• other_error for exceptions indicating other library errors

Version history

• Since version 3.0.0.