@brief Installs user defined format specifier and handler

defined(ELPP_FEATURE_ALL) || defined(ELPP_FEATURE_CRASH_LOG) @brief Installs pre rollout callback, this callback is triggered when log file is about t

@brief Checks if character is digit. Dont use libc implementation of it to prevent locale issues.

@brief return whether value is discarded @sa https://json.nlohmann.me/api/basic_json/is_discarded/

@brief return whether type is primitive @sa https://json.nlohmann.me/api/basic_json/is_primitive/

@brief helper to access iterator member functions in range-based for @sa https://json.nlohmann.me/api/basic_json/items/

construct iteration proxy from a container

@brief create JSON pointer @sa https://json.nlohmann.me/api/json_pointer/json_pointer/

create reverse iterator from iterator

! @param[in,out] r reference to a JSON value that is manipulated while parsing @param[in] allow_exceptions_ whether p

default constructor (for null values)

return the key of an object iterator

@brief Gets level of current configuration