tt::error_info Class Reference

#include <ttauri/error_info.hpp>

Public Member Functions
	error_info (source_location location) noexcept
	Open an error info transaction.
	error_info (bool reopen) noexcept
	Reopen a error info transaction.
	error_info (error_info &&rhs) noexcept=delete
error_info &	operator= (error_info &&rhs) noexcept=delete
	error_info (error_info const &rhs)=delete
error_info &	operator= (error_info const &rhs)=delete
template<basic_fixed_string Tag, typename Arg >
error_info &	set (Arg &&value) noexcept
	Set an information for a given tag.

Static Public Member Functions
static void	close () noexcept
	Close the current transaction.
template<typename ValueType , basic_fixed_string Tag>
static std::optional< ValueType >	pop () noexcept
	Destructive read data from the current transaction.
template<typename ValueType , basic_fixed_string Tag>
static std::optional< ValueType >	peek () noexcept
	Non-destructive read data from the current transaction.
static std::string	string () noexcept
	Return the list of entries with their current set value.

Detailed Description

Error information passed alongside an error code or exception.

Example:

try {
    try {
        tt_error_info().set<"errno">(errno);
        throw std::runtime_error("foo");
 
    } catch (runtime_error const &e) {
        // Add more information during the catch.
        tt::error_info(true).set<"url">(file_url);
        throw
    }
} catch (runtime_error const &e) {
    auto error_url = *tt::error_info::pop<URL, "url">();
    auto error_errno = *tt::error_info::pop<int, "errno">();
    tt_log_error("Config file error in file {}, errno={}", error_url, error_errno);
}

Constructor & Destructor Documentation

error_info() [1/2]

tt::error_info::error_info ( source_location location )

inlinenoexcept

Open an error info transaction.

A transaction may only be opened when the error_info is in idle state; just before throwing an exception.

error_info() [2/2]

tt::error_info::error_info ( bool reopen )

inlinenoexcept

Reopen a error info transaction.

A closed transaction may be reopened to add more information to a thrown exception. Used when (re-)throwing an exception from a catch block.

Parameters

reopen

True when reopening an error_info transaction. Must be set to true.

Member Function Documentation

close()

static void tt::error_info::close ( )

inlinestaticnoexcept

Close the current transaction.

After the transaction is closed it can no longer be reopened or written to.

This function should be called in a non-throwing catch block, either directly or through the usage of error_info::pop or to_string(std::exception &e, bool)

peek()

template<typename ValueType , basic_fixed_string Tag>

static std::optional< ValueType > tt::error_info::peek ( )

inlinestaticnoexcept

Non-destructive read data from the current transaction.

This function will NOT close the current transaction.

Template Parameters

Tag	a struct type used as an identifier. This struct type should have a public typedef of value_type for the value returned by this function.

Returns

The value to if it was set, or empty.

pop()

template<typename ValueType , basic_fixed_string Tag>

static std::optional< ValueType > tt::error_info::pop ( )

inlinestaticnoexcept

Destructive read data from the current transaction.

This function will close the current transaction. Continued pop() and peek() calls will still be able to read from the current, but closed, transaction.

Template Parameters

Tag	a struct type used as an identifier. This struct type should have a public typedef of value_type for the value returned by this function.

Returns

The value to if it was set, or empty.

set()

template<basic_fixed_string Tag, typename Arg >

error_info & tt::error_info::set ( Arg && value )

inlinenoexcept

Set an information for a given tag.

You can chain multiple .set() calls.

Template Parameters

Tag	a struct type used as an identifier. This struct type should have a public typedef of value_type for the value set in this function.

Parameters

value

The value to set.

Returns

A reference to the error_info, for chaining of .set() calls.

string()

static std::string tt::error_info::string ( )

inlinestaticnoexcept

Return the list of entries with their current set value.

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The documentation for this class was generated from the following file:

• hikogui/src/ttauri/error_info.hpp