2 ''' $RCSfile$$Revision$$Date$
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37 ''' string Tr holds user defined translation string.
38 ''' Bell System Logo is used as a dummy character.
44 .if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
45 .if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
48 ''' \*(M", \*(S", \*(N" and \*(T" are the equivalent of
49 ''' \*(L" and \*(R", except that they are used on ".xx" lines,
50 ''' such as .IP and .SH, which do another additional levels of
51 ''' double-quote interpretation
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81 .\" index entries out stderr for the following things:
86 .\" X<> Xref (embedded
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88 .\" in some meaninful fashion.
91 .tm Index:\\$1\t\\n%\t"\\$2"
96 .TH BIO_ctrl 3 "0.9.7d" "2/Sep/2004" "OpenSSL"
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171 .if \n(.H>23 .if \n(.V>19 \
175 . ds v \h'-1'\o'\(aa\(ga'
191 BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset,
192 BIO_seek, BIO_tell, BIO_flush, BIO_eof, BIO_set_close, BIO_get_close,
193 BIO_pending, BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending,
194 BIO_get_info_callback, BIO_set_info_callback \- BIO control operations
198 \& #include <openssl/bio.h>
201 \& long BIO_ctrl(BIO *bp,int cmd,long larg,void *parg);
202 \& long BIO_callback_ctrl(BIO *b, int cmd, void (*fp)(struct bio_st *, int, const char *, int, long, long));
203 \& char * BIO_ptr_ctrl(BIO *bp,int cmd,long larg);
204 \& long BIO_int_ctrl(BIO *bp,int cmd,long larg,int iarg);
207 \& int BIO_reset(BIO *b);
208 \& int BIO_seek(BIO *b, int ofs);
209 \& int BIO_tell(BIO *b);
210 \& int BIO_flush(BIO *b);
211 \& int BIO_eof(BIO *b);
212 \& int BIO_set_close(BIO *b,long flag);
213 \& int BIO_get_close(BIO *b);
214 \& int BIO_pending(BIO *b);
215 \& int BIO_wpending(BIO *b);
216 \& size_t BIO_ctrl_pending(BIO *b);
217 \& size_t BIO_ctrl_wpending(BIO *b);
220 \& int BIO_get_info_callback(BIO *b,bio_info_cb **cbp);
221 \& int BIO_set_info_callback(BIO *b,bio_info_cb *cb);
224 \& typedef void bio_info_cb(BIO *b, int oper, const char *ptr, int arg1, long arg2, long arg3);
227 \fIBIO_ctrl()\fR, \fIBIO_callback_ctrl()\fR, \fIBIO_ptr_ctrl()\fR and \fIBIO_int_ctrl()\fR
228 are BIO \*(L"control\*(R" operations taking arguments of various types.
229 These functions are not normally called directly, various macros
230 are used instead. The standard macros are described below, macros
231 specific to a particular type of BIO are described in the specific
232 BIOs manual page as well as any special features of the standard
235 \fIBIO_reset()\fR typically resets a BIO to some initial state, in the case
236 of file related BIOs for example it rewinds the file pointer to the
239 \fIBIO_seek()\fR resets a file related BIO's (that is file descriptor and
240 FILE BIOs) file position pointer to \fBofs\fR bytes from start of file.
242 \fIBIO_tell()\fR returns the current file position of a file related BIO.
244 \fIBIO_flush()\fR normally writes out any internally buffered data, in some
245 cases it is used to signal EOF and that no more data will be written.
247 \fIBIO_eof()\fR returns 1 if the BIO has read EOF, the precise meaning of
248 \*(L"EOF\*(R" varies according to the BIO type.
250 \fIBIO_set_close()\fR sets the BIO \fBb\fR close flag to \fBflag\fR. \fBflag\fR can
251 take the value BIO_CLOSE or BIO_NOCLOSE. Typically BIO_CLOSE is used
252 in a source/sink BIO to indicate that the underlying I/O stream should
253 be closed when the BIO is freed.
255 \fIBIO_get_close()\fR returns the BIOs close flag.
257 \fIBIO_pending()\fR, \fIBIO_ctrl_pending()\fR, \fIBIO_wpending()\fR and \fIBIO_ctrl_wpending()\fR
258 return the number of pending characters in the BIOs read and write buffers.
259 Not all BIOs support these calls. \fIBIO_ctrl_pending()\fR and \fIBIO_ctrl_wpending()\fR
260 return a size_t type and are functions, \fIBIO_pending()\fR and \fIBIO_wpending()\fR are
261 macros which call \fIBIO_ctrl()\fR.
263 \fIBIO_reset()\fR normally returns 1 for success and 0 or \-1 for failure. File
264 BIOs are an exception, they return 0 for success and \-1 for failure.
266 \fIBIO_seek()\fR and \fIBIO_tell()\fR both return the current file position on success
267 and \-1 for failure, except file BIOs which for \fIBIO_seek()\fR always return 0
268 for success and \-1 for failure.
270 \fIBIO_flush()\fR returns 1 for success and 0 or \-1 for failure.
272 \fIBIO_eof()\fR returns 1 if EOF has been reached 0 otherwise.
274 \fIBIO_set_close()\fR always returns 1.
276 \fIBIO_get_close()\fR returns the close flag value: BIO_CLOSE or BIO_NOCLOSE.
278 \fIBIO_pending()\fR, \fIBIO_ctrl_pending()\fR, \fIBIO_wpending()\fR and \fIBIO_ctrl_wpending()\fR
279 return the amount of pending data.
281 \fIBIO_flush()\fR, because it can write data may return 0 or \-1 indicating
282 that the call should be retried later in a similar manner to \fIBIO_write()\fR.
283 The \fIBIO_should_retry()\fR call should be used and appropriate action taken
286 The return values of \fIBIO_pending()\fR and \fIBIO_wpending()\fR may not reliably
287 determine the amount of pending data in all cases. For example in the
288 case of a file BIO some data may be available in the FILE structures
289 internal buffers but it is not possible to determine this in a
290 portably way. For other types of BIO they may not be supported.
292 Filter BIOs if they do not internally handle a particular \fIBIO_ctrl()\fR
293 operation usually pass the operation to the next BIO in the chain.
294 This often means there is no need to locate the required BIO for
295 a particular operation, it can be called on a chain and it will
296 be automatically passed to the relevant BIO. However this can cause
297 unexpected results: for example no current filter BIOs implement
298 \fIBIO_seek()\fR, but this may still succeed if the chain ends in a FILE
299 or file descriptor BIO.
301 Source/sink BIOs return an 0 if they do not recognize the \fIBIO_ctrl()\fR
304 Some of the return values are ambiguous and care should be taken. In
305 particular a return value of 0 can be returned if an operation is not
306 supported, if an error occurred, if EOF has not been reached and in
307 the case of \fIBIO_seek()\fR on a file BIO for a successful operation.
312 .IX Title "BIO_ctrl 3"
313 .IX Name "BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset,
314 BIO_seek, BIO_tell, BIO_flush, BIO_eof, BIO_set_close, BIO_get_close,
315 BIO_pending, BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending,
316 BIO_get_info_callback, BIO_set_info_callback - BIO control operations"
320 .IX Header "SYNOPSIS"
322 .IX Header "DESCRIPTION"
324 .IX Header "RETURN VALUES"
330 .IX Header "SEE ALSO"