1BIO_s_fd(3)                         OpenSSL                        BIO_s_fd(3)
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NAME

6       BIO_s_fd, BIO_set_fd, BIO_get_fd, BIO_new_fd - file descriptor BIO
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SYNOPSIS

9        #include <openssl/bio.h>
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11        BIO_METHOD *   BIO_s_fd(void);
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13        #define BIO_set_fd(b,fd,c)     BIO_int_ctrl(b,BIO_C_SET_FD,c,fd)
14        #define BIO_get_fd(b,c)        BIO_ctrl(b,BIO_C_GET_FD,0,(char *)c)
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16        BIO *BIO_new_fd(int fd, int close_flag);
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DESCRIPTION

19       BIO_s_fd() returns the file descriptor BIO method. This is a wrapper
20       round the platforms file descriptor routines such as read() and
21       write().
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23       BIO_read() and BIO_write() read or write the underlying descriptor.
24       BIO_puts() is supported but BIO_gets() is not.
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26       If the close flag is set then then close() is called on the underlying
27       file descriptor when the BIO is freed.
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29       BIO_reset() attempts to change the file pointer to the start of file
30       using lseek(fd, 0, 0).
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32       BIO_seek() sets the file pointer to position ofs from start of file
33       using lseek(fd, ofs, 0).
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35       BIO_tell() returns the current file position by calling lseek(fd, 0,
36       1).
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38       BIO_set_fd() sets the file descriptor of BIO b to fd and the close flag
39       to c.
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41       BIO_get_fd() places the file descriptor in c if it is not NULL, it also
42       returns the file descriptor. If c is not NULL it should be of type (int
43       *).
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45       BIO_new_fd() returns a file descriptor BIO using fd and close_flag.
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NOTES

48       The behaviour of BIO_read() and BIO_write() depends on the behavior of
49       the platforms read() and write() calls on the descriptor. If the
50       underlying file descriptor is in a non blocking mode then the BIO will
51       behave in the manner described in the BIO_read(3) and
52       BIO_should_retry(3) manual pages.
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54       File descriptor BIOs should not be used for socket I/O. Use socket BIOs
55       instead.
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RETURN VALUES

58       BIO_s_fd() returns the file descriptor BIO method.
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60       BIO_reset() returns zero for success and -1 if an error occurred.
61       BIO_seek() and BIO_tell() return the current file position or -1 is an
62       error occurred. These values reflect the underlying lseek() behaviour.
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64       BIO_set_fd() always returns 1.
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66       BIO_get_fd() returns the file descriptor or -1 if the BIO has not been
67       initialized.
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69       BIO_new_fd() returns the newly allocated BIO or NULL is an error
70       occurred.
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EXAMPLE

73       This is a file descriptor BIO version of "Hello World":
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75        BIO *out;
76        out = BIO_new_fd(fileno(stdout), BIO_NOCLOSE);
77        BIO_printf(out, "Hello World\n");
78        BIO_free(out);
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SEE ALSO

81       BIO_seek(3), BIO_tell(3), BIO_reset(3), BIO_read(3), BIO_write(3),
82       BIO_puts(3), BIO_gets(3), BIO_printf(3), BIO_set_close(3),
83       BIO_get_close(3)
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871.0.2o                            2020-01-28                       BIO_s_fd(3)
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