diff options
author | Dr. Stephen Henson <steve@openssl.org> | 2000-09-10 01:52:26 +0000 |
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committer | Dr. Stephen Henson <steve@openssl.org> | 2000-09-10 01:52:26 +0000 |
commit | d7b9c76c72bd6e744db2070d148738941ba38305 (patch) | |
tree | 46480be11f8b6bac37f3f2052d6b262261a85a91 /doc/crypto/BIO_s_file.pod | |
parent | 0baed24c1b2d9a1e53d9f81cf805ac65d68096b3 (diff) |
More preliminary BIO docs...
Incomplete and possibly inaccurate. Hope somone is
checking these :-)
Diffstat (limited to 'doc/crypto/BIO_s_file.pod')
-rw-r--r-- | doc/crypto/BIO_s_file.pod | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/doc/crypto/BIO_s_file.pod b/doc/crypto/BIO_s_file.pod new file mode 100644 index 0000000000..b46c88c41b --- /dev/null +++ b/doc/crypto/BIO_s_file.pod @@ -0,0 +1,130 @@ +=pod + +=head1 NAME + + BIO_s_file - FILE bio. + +=head1 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); + + BIO_seek(BIO *b,int offset); + int BIO_tell(BIO *b); + + 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() 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() on a file BIO calls fseek() to reset the position indicator +to the start of the file. + +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() set 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. + +=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 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_read_filename(out, "filename.txt")) /* Error ... */ + BIO_printf(out, "Hello World\n"); + BIO_free(out); + +=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 SEE ALSO + +TBA |