:-'Generic Commit'

dropshell-tool/openssl-1.1.1w/doc/man3/BIO_s_file.pod

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+=pod
+
+=head1 NAME
+
+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
+
+=head1 SYNOPSIS
+
+ #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)
+
+=head1 DESCRIPTION
+
+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.
+
+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.
+
+BIO_flush() on a file BIO calls the fflush() function on the wrapped
+stream.
+
+BIO_reset() attempts to change the file pointer to the start of file
+using fseek(stream, 0, 0).
+
+BIO_seek() sets the file pointer to position B<ofs> from start of file
+using fseek(stream, ofs, 0).
+
+BIO_eof() calls feof().
+
+Setting the BIO_CLOSE flag calls fclose() on the stream when the BIO
+is freed.
+
+BIO_new_file() creates a new file BIO with mode B<mode> the meaning
+of B<mode> is the same as the stdio function fopen(). The BIO_CLOSE
+flag is set on the returned BIO.
+
+BIO_new_fp() creates a file BIO wrapping B<stream>. 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).
+
+BIO_set_fp() sets the fp of a file BIO to B<fp>. B<flags> has the same
+meaning as in BIO_new_fp(), it is a macro.
+
+BIO_get_fp() retrieves the fp of a file BIO, it is a macro.
+
+BIO_seek() is a macro that sets the position pointer to B<offset> bytes
+from the start of file.
+
+BIO_tell() returns the value of the position pointer.
+
+BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
+BIO_rw_filename() set the file BIO B<b> to use file B<name> for
+reading, writing, append or read write respectively.
+
+=head1 NOTES
+
+When wrapping stdout, stdin or stderr the underlying stream should not
+normally be closed so the BIO_NOCLOSE flag should be set.
+
+Because the file BIO calls the underlying stdio functions any quirks
+in stdio behaviour will be mirrored by the corresponding BIO.
+
+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.
+
+=head1 RETURN VALUES
+
+BIO_s_file() returns the file BIO method.
+
+BIO_new_file() and BIO_new_fp() return a file BIO or NULL if an error
+occurred.
+
+BIO_set_fp() and BIO_get_fp() return 1 for success or 0 for failure
+(although the current implementation never return 0).
+
+BIO_seek() returns the same value as the underlying fseek() function:
+0 for success or -1 for failure.
+
+BIO_tell() returns the current file position.
+
+BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
+BIO_rw_filename() return 1 for success or 0 for failure.
+
+=head1 EXAMPLES
+
+File BIO "hello world":
+
+ BIO *bio_out;
+
+ bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
+ BIO_printf(bio_out, "Hello World\n");
+
+Alternative technique:
+
+ 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");
+
+Write to a file:
+
+ BIO *out;
+
+ out = BIO_new_file("filename.txt", "w");
+ if (!out)
+     /* Error */
+ BIO_printf(out, "Hello World\n");
+ BIO_free(out);
+
+Alternative technique:
+
+ 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);
+
+=head1 BUGS
+
+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.
+
+=head1 SEE ALSO
+
+L<BIO_seek(3)>, L<BIO_tell(3)>,
+L<BIO_reset(3)>, L<BIO_flush(3)>,
+L<BIO_read_ex(3)>,
+L<BIO_write_ex(3)>, L<BIO_puts(3)>,
+L<BIO_gets(3)>, L<BIO_printf(3)>,
+L<BIO_set_close(3)>, L<BIO_get_close(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
+
+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
+L<https://www.openssl.org/source/license.html>.
+
+=cut