BIO_new_file(3ssl)

1BIO_s_file(3)                       OpenSSL                      BIO_s_file(3)
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NAME

6       BIO_s_file, BIO_new_file, BIO_new_fp, BIO_set_fp, BIO_get_fp,
7       BIO_read_filename, BIO_write_filename, BIO_append_filename,
8       BIO_rw_filename - FILE bio
9

SYNOPSIS

11        #include <openssl/bio.h>
12
13        BIO_METHOD *   BIO_s_file(void);
14        BIO *BIO_new_file(const char *filename, const char *mode);
15        BIO *BIO_new_fp(FILE *stream, int flags);
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17        BIO_set_fp(BIO *b,FILE *fp, int flags);
18        BIO_get_fp(BIO *b,FILE **fpp);
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20        int BIO_read_filename(BIO *b, char *name)
21        int BIO_write_filename(BIO *b, char *name)
22        int BIO_append_filename(BIO *b, char *name)
23        int BIO_rw_filename(BIO *b, char *name)
24

DESCRIPTION

26       BIO_s_file() returns the BIO file method. As its name implies it is a
27       wrapper round the stdio FILE structure and it is a source/sink BIO.
28
29       Calls to BIO_read() and BIO_write() read and write data to the underly‐
30       ing stream. BIO_gets() and BIO_puts() are supported on file BIOs.
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32       BIO_flush() on a file BIO calls the fflush() function on the wrapped
33       stream.
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35       BIO_reset() attempts to change the file pointer to the start of file
36       using fseek(stream, 0, 0).
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38       BIO_seek() sets the file pointer to position ofs from start of file
39       using fseek(stream, ofs, 0).
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41       BIO_eof() calls feof().
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43       Setting the BIO_CLOSE flag calls fclose() on the stream when the BIO is
44       freed.
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46       BIO_new_file() creates a new file BIO with mode mode the meaning of
47       mode is the same as the stdio function fopen(). The BIO_CLOSE flag is
48       set on the returned BIO.
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50       BIO_new_fp() creates a file BIO wrapping stream. Flags can be:
51       BIO_CLOSE, BIO_NOCLOSE (the close flag) BIO_FP_TEXT (sets the underly‐
52       ing stream to text mode, default is binary: this only has any effect
53       under Win32).
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55       BIO_set_fp() set the fp of a file BIO to fp. flags has the same meaning
56       as in BIO_new_fp(), it is a macro.
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58       BIO_get_fp() retrieves the fp of a file BIO, it is a macro.
59
60       BIO_seek() is a macro that sets the position pointer to offset bytes
61       from the start of file.
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63       BIO_tell() returns the value of the position pointer.
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65       BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
66       BIO_rw_filename() set the file BIO b to use file name for reading,
67       writing, append or read write respectively.
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NOTES

70       When wrapping stdout, stdin or stderr the underlying stream should not
71       normally be closed so the BIO_NOCLOSE flag should be set.
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73       Because the file BIO calls the underlying stdio functions any quirks in
74       stdio behaviour will be mirrored by the corresponding BIO.
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EXAMPLES

77       File BIO "hello world":
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79        BIO *bio_out;
80        bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
81        BIO_printf(bio_out, "Hello World\n");
82
83       Alternative technique:
84
85        BIO *bio_out;
86        bio_out = BIO_new(BIO_s_file());
87        if(bio_out == NULL) /* Error ... */
88        if(!BIO_set_fp(bio_out, stdout, BIO_NOCLOSE)) /* Error ... */
89        BIO_printf(bio_out, "Hello World\n");
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91       Write to a file:
92
93        BIO *out;
94        out = BIO_new_file("filename.txt", "w");
95        if(!out) /* Error occurred */
96        BIO_printf(out, "Hello World\n");
97        BIO_free(out);
98
99       Alternative technique:
100
101        BIO *out;
102        out = BIO_new(BIO_s_file());
103        if(out == NULL) /* Error ... */
104        if(!BIO_write_filename(out, "filename.txt")) /* Error ... */
105        BIO_printf(out, "Hello World\n");
106        BIO_free(out);
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RETURN VALUES

109       BIO_s_file() returns the file BIO method.
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111       BIO_new_file() and BIO_new_fp() return a file BIO or NULL if an error
112       occurred.
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114       BIO_set_fp() and BIO_get_fp() return 1 for success or 0 for failure
115       (although the current implementation never return 0).
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117       BIO_seek() returns the same value as the underlying fseek() function: 0
118       for success or -1 for failure.
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120       BIO_tell() returns the current file position.
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122       BIO_read_filename(), BIO_write_filename(),  BIO_append_filename() and
123       BIO_rw_filename() return 1 for success or 0 for failure.
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BUGS

126       BIO_reset() and BIO_seek() are implemented using fseek() on the under‐
127       lying stream. The return value for fseek() is 0 for success or -1 if an
128       error occurred this differs from other types of BIO which will typi‐
129       cally return 1 for success and a non positive value if an error
130       occurred.
131