std::system...system_error(3)

💖 NAME 💖

std::system_error::system_error - std::system_error::system_error

okay so bestie, this is std::system...system_error(3) from the C++ Standard Libary manual — yes, that’s the manual name, and the page is literally giving the same std::system_error::system_error on both sides of the dash 😭💅. iconic, mysterious, a little redundant, we love her.

✨ Synopsis ✨

system_error( std::error_code ec );                              (1)
(since C++11)
system_error( std::error_code ec, const std::string& what_arg ); (2)
(since C++11)
system_error( std::error_code ec, const char* what_arg );        (2)
(since C++11)
system_error( int ev, const std::error_category& ecat );         (3)
(since C++11)
system_error( int ev, const std::error_category& ecat,           (4)
(since C++11)
              const std::string& what_arg );
system_error( int ev, const std::error_category& ecat,           (4)
(since C++11)
              const char* what_arg );
system_error( const system_error& other ) noexcept;              (5)
(since C++11)

Constructs new system error object. that’s the whole assignment, no cap ✨:

1. Constructs with error code ec.
2. Constructs with error code ec and explanation string what_arg. The string returned by what() is guaranteed to contain what_arg as a substring.
3. Constructs with underlying error code ev and associated error category ecat.
4. Constructs with underlying error code ev, associated error category ecat and explanatory string what_arg. The string returned by what() is guaranteed to contain what_arg as a substring (assuming that it doesn't contain an embedded null character).
5. Copy constructor. Initializes the contents with those of other. If *this and other both have dynamic type std::system_error then std::strcmp(what(), other.what()) == 0.

🎀 Parameters 🎀

• ec — error code.
• ev — underlying error code in the enumeration associated with ecat.
• ecat — the category of error.
• what_arg — explanatory string.
• other — another system_error to copy.

💻 Example 💻

Demonstrates how to create a system_error exception from an errno value. yes bestie, error-handling main character energy 🔥.

The page even hits you with // Run this code right before the snippet:

#include <iostream>
#include <system_error>

int main()
{
    try
    {
        throw std::system_error(EDOM, std::generic_category(), "FIX ME");
    }
    catch (const std::system_error& ex)
    {
        std::cout << "code:    [" << ex.code() << "]\n"
                     "message: [" << ex.code().message() << "]\n"
                     "what:    [" << ex.what() << "]\n";
    }
}

🌈 Possible output: 🌈

code:    [generic:33]
message: [Numerical argument out of domain]
what:    [FIX ME: Numerical argument out of domain]

mwah 💋 this page is from http://cppreference.com, dated 2024.06.10, and the footer calls it std::system...system_error(3) — periodt. 🎀✨