← Back
Editing: BIO_rw_filename.html
<?xml version="1.0" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>BIO_s_file</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <link rev="made" href="mailto:root@localhost" /> </head> <body> <ul id="index"> <li><a href="#NAME">NAME</a></li> <li><a href="#SYNOPSIS">SYNOPSIS</a></li> <li><a href="#DESCRIPTION">DESCRIPTION</a></li> <li><a href="#NOTES">NOTES</a></li> <li><a href="#RETURN-VALUES">RETURN VALUES</a></li> <li><a href="#EXAMPLES">EXAMPLES</a></li> <li><a href="#BUGS">BUGS</a></li> <li><a href="#SEE-ALSO">SEE ALSO</a></li> <li><a href="#COPYRIGHT">COPYRIGHT</a></li> </ul> <h1 id="NAME">NAME</h1> <p>BIO_s_file, BIO_new_file, BIO_new_fp, BIO_set_fp, BIO_get_fp, BIO_read_filename, BIO_write_filename, BIO_append_filename, BIO_rw_filename - FILE bio</p> <h1 id="SYNOPSIS">SYNOPSIS</h1> <pre><code> #include <openssl/bio.h> const BIO_METHOD *BIO_s_file(void); BIO *BIO_new_file(const char *filename, const char *mode); BIO *BIO_new_fp(FILE *stream, int flags); BIO_set_fp(BIO *b, FILE *fp, int flags); BIO_get_fp(BIO *b, FILE **fpp); int BIO_read_filename(BIO *b, char *name) int BIO_write_filename(BIO *b, char *name) int BIO_append_filename(BIO *b, char *name) int BIO_rw_filename(BIO *b, char *name)</code></pre> <h1 id="DESCRIPTION">DESCRIPTION</h1> <p>BIO_s_file() returns the BIO file method. As its name implies it is a wrapper round the stdio FILE structure and it is a source/sink BIO.</p> <p>Calls to BIO_read_ex() and BIO_write_ex() read and write data to the underlying stream. BIO_gets() and BIO_puts() are supported on file BIOs.</p> <p>BIO_flush() on a file BIO calls the fflush() function on the wrapped stream.</p> <p>BIO_reset() attempts to change the file pointer to the start of file using fseek(stream, 0, 0).</p> <p>BIO_seek() sets the file pointer to position <b>ofs</b> from start of file using fseek(stream, ofs, 0).</p> <p>BIO_eof() calls feof().</p> <p>Setting the BIO_CLOSE flag calls fclose() on the stream when the BIO is freed.</p> <p>BIO_new_file() creates a new file BIO with mode <b>mode</b> the meaning of <b>mode</b> is the same as the stdio function fopen(). The BIO_CLOSE flag is set on the returned BIO.</p> <p>BIO_new_fp() creates a file BIO wrapping <b>stream</b>. Flags can be: BIO_CLOSE, BIO_NOCLOSE (the close flag) BIO_FP_TEXT (sets the underlying stream to text mode, default is binary: this only has any effect under Win32).</p> <p>BIO_set_fp() sets the fp of a file BIO to <b>fp</b>. <b>flags</b> has the same meaning as in BIO_new_fp(), it is a macro.</p> <p>BIO_get_fp() retrieves the fp of a file BIO, it is a macro.</p> <p>BIO_seek() is a macro that sets the position pointer to <b>offset</b> bytes from the start of file.</p> <p>BIO_tell() returns the value of the position pointer.</p> <p>BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and BIO_rw_filename() set the file BIO <b>b</b> to use file <b>name</b> for reading, writing, append or read write respectively.</p> <h1 id="NOTES">NOTES</h1> <p>When wrapping stdout, stdin or stderr the underlying stream should not normally be closed so the BIO_NOCLOSE flag should be set.</p> <p>Because the file BIO calls the underlying stdio functions any quirks in stdio behaviour will be mirrored by the corresponding BIO.</p> <p>On Windows BIO_new_files reserves for the filename argument to be UTF-8 encoded. In other words if you have to make it work in multi- lingual environment, encode filenames in UTF-8.</p> <h1 id="RETURN-VALUES">RETURN VALUES</h1> <p>BIO_s_file() returns the file BIO method.</p> <p>BIO_new_file() and BIO_new_fp() return a file BIO or NULL if an error occurred.</p> <p>BIO_set_fp() and BIO_get_fp() return 1 for success or 0 for failure (although the current implementation never return 0).</p> <p>BIO_seek() returns the same value as the underlying fseek() function: 0 for success or -1 for failure.</p> <p>BIO_tell() returns the current file position.</p> <p>BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and BIO_rw_filename() return 1 for success or 0 for failure.</p> <h1 id="EXAMPLES">EXAMPLES</h1> <p>File BIO "hello world":</p> <pre><code> BIO *bio_out; bio_out = BIO_new_fp(stdout, BIO_NOCLOSE); BIO_printf(bio_out, "Hello World\n");</code></pre> <p>Alternative technique:</p> <pre><code> BIO *bio_out; bio_out = BIO_new(BIO_s_file()); if (bio_out == NULL) /* Error */ if (!BIO_set_fp(bio_out, stdout, BIO_NOCLOSE)) /* Error */ BIO_printf(bio_out, "Hello World\n");</code></pre> <p>Write to a file:</p> <pre><code> BIO *out; out = BIO_new_file("filename.txt", "w"); if (!out) /* Error */ BIO_printf(out, "Hello World\n"); BIO_free(out);</code></pre> <p>Alternative technique:</p> <pre><code> BIO *out; out = BIO_new(BIO_s_file()); if (out == NULL) /* Error */ if (!BIO_write_filename(out, "filename.txt")) /* Error */ BIO_printf(out, "Hello World\n"); BIO_free(out);</code></pre> <h1 id="BUGS">BUGS</h1> <p>BIO_reset() and BIO_seek() are implemented using fseek() on the underlying stream. The return value for fseek() is 0 for success or -1 if an error occurred this differs from other types of BIO which will typically return 1 for success and a non positive value if an error occurred.</p> <h1 id="SEE-ALSO">SEE ALSO</h1> <p><a href="../man3/BIO_seek.html">BIO_seek(3)</a>, <a href="../man3/BIO_tell.html">BIO_tell(3)</a>, <a href="../man3/BIO_reset.html">BIO_reset(3)</a>, <a href="../man3/BIO_flush.html">BIO_flush(3)</a>, <a href="../man3/BIO_read_ex.html">BIO_read_ex(3)</a>, <a href="../man3/BIO_write_ex.html">BIO_write_ex(3)</a>, <a href="../man3/BIO_puts.html">BIO_puts(3)</a>, <a href="../man3/BIO_gets.html">BIO_gets(3)</a>, <a href="../man3/BIO_printf.html">BIO_printf(3)</a>, <a href="../man3/BIO_set_close.html">BIO_set_close(3)</a>, <a href="../man3/BIO_get_close.html">BIO_get_close(3)</a></p> <h1 id="COPYRIGHT">COPYRIGHT</h1> <p>Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.</p> <p>Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p> </body> </html>
Save File
Cancel