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BIO_set_fp (3)
  • >> BIO_set_fp (3) ( Разные man: Библиотечные вызовы )
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    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

    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() 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() set 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 behaviour will be mirrored by the corresponding BIO.  

    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);
    
    
     

    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.  

    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.  

    SEE ALSO

    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

    NAME
    SYNOPSIS
    DESCRIPTION
    NOTES
    EXAMPLES
    RETURN VALUES
    BUGS
    SEE ALSO


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