std::fclose(3)

💖 NAME 💖

okay so bestie, welcome to the std::fclose(3) page from the C++ Standard Libary — and the NAME section is literally:

std::fclose — std::fclose

yes, that’s the whole thing. short, iconic, main character energy. 💅

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✨ Synopsis ✨

It’s defined in header <cstdio>, and the signature is:

Defined in header <cstdio>
int fclose( std::FILE* stream );

So the way this works: it closes the given file stream. Any unwritten buffered data are flushed to the OS, and any unread buffered data are discarded — like, bye to the unread stuff, fr. 👋

Whether or not the operation succeeds, the stream is no longer associated with a file, and the buffer allocated by std::setbuf or std::setvbuf, if any, is also disassociated and deallocated if automatic allocation was used. no cap, that happens either way. 💖

⚠️ The behavior is undefined if the value of the pointer stream is used after fclose returns. translation: after close, do not touch stream — that’s undefined behavior, and undefined behavior is not cute. 💀

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🌸 Parameters 🌸

• stream — the file stream to close. that’s the whole parameter list, bestie. 🫶

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🎀 Return value 🎀

• 0 on success, EOF otherwise. slay. ✨

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🦋 Example 🦋

The page says // Run this code, so bestie, run it — full example, preserved exactly:

        #include <cstdio>
        #include <cstdlib>

        int main()
        {
            int is_ok = EXIT_FAILURE;
            FILE* fp = std::fopen("/tmp/test.txt", "w+");
            if (!fp)
            {
                std::perror("File opening failed");
                return is_ok;
            }

            int c; // Note: int, not char, required to handle EOF
            while ((c = std::fgetc(fp)) != EOF) // Standard C I/O file reading
       loop
                std::putchar(c);

            if (std::ferror(fp))
                std::puts("I/O error when reading");
            else if (std::feof(fp))
            {
                std::puts("End of file reached successfully");
                is_ok = EXIT_SUCCESS;
            }

            std::fclose(fp);
            return is_ok;
        }

Output, when it runs:

End of file reached successfully

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🌈 See also 🌈

• fopen — opens a file (function). 🔥
• freopen — open an existing stream with a different name (function). 🌟
• close — flushes the put area buffer and closes the associated file (public member function of std::basic_filebuf<CharT,Traits>). 👑
• C documentation for fclose. 💜

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xoxo, your Unix bestie 💅 — this page comes from the C++ Standard Libary, source/version: http://cppreference.com, date: 2024.06.10, and the manual page is std::fclose(3). bye bestie, close those streams responsibly! 🎀🦋