std::streamoff(3)

🌸 std::streamoff(3) — C++ Standard Library, section 3 💅

okay bestie, so this is the std::streamoff page from the C++ Standard Library, manual section 3 — and honestly? it's a tiny little typedef with main character energy. let's get into it 🫶

✨ NAME ✨

std::streamoff — literally just std::streamoff, no notes, she's her own name, iconic 👑

🦋 Synopsis 🦋

first things first, where does she live? defined in header <ios>, periodt:

typedef /*implementation-defined*/ streamoff;

so the type std::streamoff is an implementation-defined signed integral type — since C++11, bestie, keep up 😌 — and it's big enough to represent the maximum possible file size supported by your operating system. like, whatever the biggest file your OS can even dream of, this type can hold an offset into it. slay.

typically, this is an alias for long long. (since C++11) 💖

what's she for? she's used to represent offsets from stream positions (aka values of type std::fpos). and here's the spicy part: a std::streamoff value constructed from -1 is also used to represent error conditions by some of the I/O library functions. so like, -1 is the "something went wrong" girlie in certain corners of the I/O lib 🚩

💫 Relationship with std::fpos 💫

the way these two are lowkey besties — here's the whole dynamic:

• the difference between two std::fpos objects is a value of type std::streamoff
• a value of type std::streamoff may be added or subtracted from std::fpos, yielding a different std::fpos
• a value of type std::fpos is implicitly convertible to std::streamoff (the conversion result is the offset from the beginning of the file)
• a value of type std::fpos is constructible from a value of type std::streamoff

like. math but make it stream positions. we love a convertible duo 🧚

🔥 See also 🔥

• fpos — represents absolute position in a stream or a file (class template) 🎀
• seekg — sets the input position indicator (public member function of std::basic_istream<CharT,Traits>) 👀
• seekp — sets the output position indicator (public member function of std::basic_ostream<CharT,Traits>) ✍️

ngl the whole takeaway is: std::streamoff = the big signed integer that measures how far you are from somewhere in a stream, and -1 sometimes means "oops, error" in I/O land. write that down bestie 💀💖

okay that's the whole page, and now the cute sign-off: this lil slice of documentation came from http://cppreference.com, dated 2024.06.10, and you can find it filed under std::streamoff(3) in section 3 of the manual 🌈✨ bye bestie, go read your streams 🦋💜