Index for Section 3

Alphabetical listing for B

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BIO_s_file(3)
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

SYNOPSIS
  #include <openssl/bio.h>

  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 );

DESCRIPTION
  The BIO_s_file() function 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() and BIO_write() 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 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 mode the meaning of 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 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 fp.	 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 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 to use file name for reading, writing,
  append or read write respectively.

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 behavior will be mirrored by the corresponding BIO.

RESTRICTIONS
  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 nonpositive value if an error occurred.

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 returns 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.

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 occurred */
       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);

SEE ALSO
  Functions: BIO_seek(3), BIO_tell(3), BIO_reset(3), BIO_flush(3),
  BIO_read(3), BIO_write(3), BIO_puts(3), BIO_gets(3), BIO_printf(3),
  BIO_set_close(3), BIO_get_close(3)

Index for Section 3

Alphabetical listing for B

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