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129.\" ========================================================================
130.\"
131.IX Title "BIO_ctrl 3"
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124.\" ========================================================================
125.\"
126.IX Title "BIO_ctrl 3"
|
132.TH BIO_ctrl 3 "2010-03-24" "0.9.8n" "OpenSSL"
| 127.TH BIO_ctrl 3 "2010-11-16" "0.9.8p" "OpenSSL"
128.\" For nroff, turn off justification. Always turn off hyphenation; it makes
129.\" way too many mistakes in technical documents.
130.if n .ad l
131.nh
|
133.SH "NAME"
134BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset,
135BIO_seek, BIO_tell, BIO_flush, BIO_eof, BIO_set_close, BIO_get_close,
136BIO_pending, BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending,
137BIO_get_info_callback, BIO_set_info_callback \- BIO control operations
138.SH "SYNOPSIS"
139.IX Header "SYNOPSIS"
140.Vb 1
141\& #include <openssl/bio.h>
| 132.SH "NAME"
133BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset,
134BIO_seek, BIO_tell, BIO_flush, BIO_eof, BIO_set_close, BIO_get_close,
135BIO_pending, BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending,
136BIO_get_info_callback, BIO_set_info_callback \- BIO control operations
137.SH "SYNOPSIS"
138.IX Header "SYNOPSIS"
139.Vb 1
140\& #include <openssl/bio.h>
|
142.Ve
143.PP
144.Vb 4
| 141\&
|
145\& long BIO_ctrl(BIO *bp,int cmd,long larg,void *parg);
146\& long BIO_callback_ctrl(BIO *b, int cmd, void (*fp)(struct bio_st *, int, const char *, int, long, long));
147\& char * BIO_ptr_ctrl(BIO *bp,int cmd,long larg);
148\& long BIO_int_ctrl(BIO *bp,int cmd,long larg,int iarg);
| 142\& long BIO_ctrl(BIO *bp,int cmd,long larg,void *parg);
143\& long BIO_callback_ctrl(BIO *b, int cmd, void (*fp)(struct bio_st *, int, const char *, int, long, long));
144\& char * BIO_ptr_ctrl(BIO *bp,int cmd,long larg);
145\& long BIO_int_ctrl(BIO *bp,int cmd,long larg,int iarg);
|
149.Ve
150.PP
151.Vb 11
| 146\&
|
152\& int BIO_reset(BIO *b);
153\& int BIO_seek(BIO *b, int ofs);
154\& int BIO_tell(BIO *b);
155\& int BIO_flush(BIO *b);
156\& int BIO_eof(BIO *b);
157\& int BIO_set_close(BIO *b,long flag);
158\& int BIO_get_close(BIO *b);
159\& int BIO_pending(BIO *b);
160\& int BIO_wpending(BIO *b);
161\& size_t BIO_ctrl_pending(BIO *b);
162\& size_t BIO_ctrl_wpending(BIO *b);
| 147\& int BIO_reset(BIO *b);
148\& int BIO_seek(BIO *b, int ofs);
149\& int BIO_tell(BIO *b);
150\& int BIO_flush(BIO *b);
151\& int BIO_eof(BIO *b);
152\& int BIO_set_close(BIO *b,long flag);
153\& int BIO_get_close(BIO *b);
154\& int BIO_pending(BIO *b);
155\& int BIO_wpending(BIO *b);
156\& size_t BIO_ctrl_pending(BIO *b);
157\& size_t BIO_ctrl_wpending(BIO *b);
|
163.Ve
164.PP
165.Vb 2
| 158\&
|
166\& int BIO_get_info_callback(BIO *b,bio_info_cb **cbp);
167\& int BIO_set_info_callback(BIO *b,bio_info_cb *cb);
| 159\& int BIO_get_info_callback(BIO *b,bio_info_cb **cbp);
160\& int BIO_set_info_callback(BIO *b,bio_info_cb *cb);
|
168.Ve
169.PP
170.Vb 1
| 161\&
|
171\& typedef void bio_info_cb(BIO *b, int oper, const char *ptr, int arg1, long arg2, long arg3);
172.Ve
173.SH "DESCRIPTION"
174.IX Header "DESCRIPTION"
175\&\fIBIO_ctrl()\fR, \fIBIO_callback_ctrl()\fR, \fIBIO_ptr_ctrl()\fR and \fIBIO_int_ctrl()\fR
176are \s-1BIO\s0 \*(L"control\*(R" operations taking arguments of various types.
177These functions are not normally called directly, various macros
178are used instead. The standard macros are described below, macros
179specific to a particular type of \s-1BIO\s0 are described in the specific
180BIOs manual page as well as any special features of the standard
181calls.
182.PP
183\&\fIBIO_reset()\fR typically resets a \s-1BIO\s0 to some initial state, in the case
184of file related BIOs for example it rewinds the file pointer to the
185start of the file.
186.PP
187\&\fIBIO_seek()\fR resets a file related \s-1BIO\s0's (that is file descriptor and
188\&\s-1FILE\s0 BIOs) file position pointer to \fBofs\fR bytes from start of file.
189.PP
190\&\fIBIO_tell()\fR returns the current file position of a file related \s-1BIO\s0.
191.PP
192\&\fIBIO_flush()\fR normally writes out any internally buffered data, in some
193cases it is used to signal \s-1EOF\s0 and that no more data will be written.
194.PP
195\&\fIBIO_eof()\fR returns 1 if the \s-1BIO\s0 has read \s-1EOF\s0, the precise meaning of
196\&\*(L"\s-1EOF\s0\*(R" varies according to the \s-1BIO\s0 type.
197.PP
198\&\fIBIO_set_close()\fR sets the \s-1BIO\s0 \fBb\fR close flag to \fBflag\fR. \fBflag\fR can
199take the value \s-1BIO_CLOSE\s0 or \s-1BIO_NOCLOSE\s0. Typically \s-1BIO_CLOSE\s0 is used
200in a source/sink \s-1BIO\s0 to indicate that the underlying I/O stream should
201be closed when the \s-1BIO\s0 is freed.
202.PP
203\&\fIBIO_get_close()\fR returns the BIOs close flag.
204.PP
205\&\fIBIO_pending()\fR, \fIBIO_ctrl_pending()\fR, \fIBIO_wpending()\fR and \fIBIO_ctrl_wpending()\fR
206return the number of pending characters in the BIOs read and write buffers.
207Not all BIOs support these calls. \fIBIO_ctrl_pending()\fR and \fIBIO_ctrl_wpending()\fR
208return a size_t type and are functions, \fIBIO_pending()\fR and \fIBIO_wpending()\fR are
209macros which call \fIBIO_ctrl()\fR.
210.SH "RETURN VALUES"
211.IX Header "RETURN VALUES"
212\&\fIBIO_reset()\fR normally returns 1 for success and 0 or \-1 for failure. File
213BIOs are an exception, they return 0 for success and \-1 for failure.
214.PP
215\&\fIBIO_seek()\fR and \fIBIO_tell()\fR both return the current file position on success
216and \-1 for failure, except file BIOs which for \fIBIO_seek()\fR always return 0
217for success and \-1 for failure.
218.PP
219\&\fIBIO_flush()\fR returns 1 for success and 0 or \-1 for failure.
220.PP
221\&\fIBIO_eof()\fR returns 1 if \s-1EOF\s0 has been reached 0 otherwise.
222.PP
223\&\fIBIO_set_close()\fR always returns 1.
224.PP
225\&\fIBIO_get_close()\fR returns the close flag value: \s-1BIO_CLOSE\s0 or \s-1BIO_NOCLOSE\s0.
226.PP
227\&\fIBIO_pending()\fR, \fIBIO_ctrl_pending()\fR, \fIBIO_wpending()\fR and \fIBIO_ctrl_wpending()\fR
228return the amount of pending data.
229.SH "NOTES"
230.IX Header "NOTES"
231\&\fIBIO_flush()\fR, because it can write data may return 0 or \-1 indicating
232that the call should be retried later in a similar manner to \fIBIO_write()\fR.
233The \fIBIO_should_retry()\fR call should be used and appropriate action taken
234is the call fails.
235.PP
236The return values of \fIBIO_pending()\fR and \fIBIO_wpending()\fR may not reliably
237determine the amount of pending data in all cases. For example in the
238case of a file \s-1BIO\s0 some data may be available in the \s-1FILE\s0 structures
239internal buffers but it is not possible to determine this in a
240portably way. For other types of \s-1BIO\s0 they may not be supported.
241.PP
242Filter BIOs if they do not internally handle a particular \fIBIO_ctrl()\fR
243operation usually pass the operation to the next \s-1BIO\s0 in the chain.
244This often means there is no need to locate the required \s-1BIO\s0 for
245a particular operation, it can be called on a chain and it will
246be automatically passed to the relevant \s-1BIO\s0. However this can cause
247unexpected results: for example no current filter BIOs implement
248\&\fIBIO_seek()\fR, but this may still succeed if the chain ends in a \s-1FILE\s0
249or file descriptor \s-1BIO\s0.
250.PP
251Source/sink BIOs return an 0 if they do not recognize the \fIBIO_ctrl()\fR
252operation.
253.SH "BUGS"
254.IX Header "BUGS"
255Some of the return values are ambiguous and care should be taken. In
256particular a return value of 0 can be returned if an operation is not
257supported, if an error occurred, if \s-1EOF\s0 has not been reached and in
| 162\& typedef void bio_info_cb(BIO *b, int oper, const char *ptr, int arg1, long arg2, long arg3);
163.Ve
164.SH "DESCRIPTION"
165.IX Header "DESCRIPTION"
166\&\fIBIO_ctrl()\fR, \fIBIO_callback_ctrl()\fR, \fIBIO_ptr_ctrl()\fR and \fIBIO_int_ctrl()\fR
167are \s-1BIO\s0 \*(L"control\*(R" operations taking arguments of various types.
168These functions are not normally called directly, various macros
169are used instead. The standard macros are described below, macros
170specific to a particular type of \s-1BIO\s0 are described in the specific
171BIOs manual page as well as any special features of the standard
172calls.
173.PP
174\&\fIBIO_reset()\fR typically resets a \s-1BIO\s0 to some initial state, in the case
175of file related BIOs for example it rewinds the file pointer to the
176start of the file.
177.PP
178\&\fIBIO_seek()\fR resets a file related \s-1BIO\s0's (that is file descriptor and
179\&\s-1FILE\s0 BIOs) file position pointer to \fBofs\fR bytes from start of file.
180.PP
181\&\fIBIO_tell()\fR returns the current file position of a file related \s-1BIO\s0.
182.PP
183\&\fIBIO_flush()\fR normally writes out any internally buffered data, in some
184cases it is used to signal \s-1EOF\s0 and that no more data will be written.
185.PP
186\&\fIBIO_eof()\fR returns 1 if the \s-1BIO\s0 has read \s-1EOF\s0, the precise meaning of
187\&\*(L"\s-1EOF\s0\*(R" varies according to the \s-1BIO\s0 type.
188.PP
189\&\fIBIO_set_close()\fR sets the \s-1BIO\s0 \fBb\fR close flag to \fBflag\fR. \fBflag\fR can
190take the value \s-1BIO_CLOSE\s0 or \s-1BIO_NOCLOSE\s0. Typically \s-1BIO_CLOSE\s0 is used
191in a source/sink \s-1BIO\s0 to indicate that the underlying I/O stream should
192be closed when the \s-1BIO\s0 is freed.
193.PP
194\&\fIBIO_get_close()\fR returns the BIOs close flag.
195.PP
196\&\fIBIO_pending()\fR, \fIBIO_ctrl_pending()\fR, \fIBIO_wpending()\fR and \fIBIO_ctrl_wpending()\fR
197return the number of pending characters in the BIOs read and write buffers.
198Not all BIOs support these calls. \fIBIO_ctrl_pending()\fR and \fIBIO_ctrl_wpending()\fR
199return a size_t type and are functions, \fIBIO_pending()\fR and \fIBIO_wpending()\fR are
200macros which call \fIBIO_ctrl()\fR.
201.SH "RETURN VALUES"
202.IX Header "RETURN VALUES"
203\&\fIBIO_reset()\fR normally returns 1 for success and 0 or \-1 for failure. File
204BIOs are an exception, they return 0 for success and \-1 for failure.
205.PP
206\&\fIBIO_seek()\fR and \fIBIO_tell()\fR both return the current file position on success
207and \-1 for failure, except file BIOs which for \fIBIO_seek()\fR always return 0
208for success and \-1 for failure.
209.PP
210\&\fIBIO_flush()\fR returns 1 for success and 0 or \-1 for failure.
211.PP
212\&\fIBIO_eof()\fR returns 1 if \s-1EOF\s0 has been reached 0 otherwise.
213.PP
214\&\fIBIO_set_close()\fR always returns 1.
215.PP
216\&\fIBIO_get_close()\fR returns the close flag value: \s-1BIO_CLOSE\s0 or \s-1BIO_NOCLOSE\s0.
217.PP
218\&\fIBIO_pending()\fR, \fIBIO_ctrl_pending()\fR, \fIBIO_wpending()\fR and \fIBIO_ctrl_wpending()\fR
219return the amount of pending data.
220.SH "NOTES"
221.IX Header "NOTES"
222\&\fIBIO_flush()\fR, because it can write data may return 0 or \-1 indicating
223that the call should be retried later in a similar manner to \fIBIO_write()\fR.
224The \fIBIO_should_retry()\fR call should be used and appropriate action taken
225is the call fails.
226.PP
227The return values of \fIBIO_pending()\fR and \fIBIO_wpending()\fR may not reliably
228determine the amount of pending data in all cases. For example in the
229case of a file \s-1BIO\s0 some data may be available in the \s-1FILE\s0 structures
230internal buffers but it is not possible to determine this in a
231portably way. For other types of \s-1BIO\s0 they may not be supported.
232.PP
233Filter BIOs if they do not internally handle a particular \fIBIO_ctrl()\fR
234operation usually pass the operation to the next \s-1BIO\s0 in the chain.
235This often means there is no need to locate the required \s-1BIO\s0 for
236a particular operation, it can be called on a chain and it will
237be automatically passed to the relevant \s-1BIO\s0. However this can cause
238unexpected results: for example no current filter BIOs implement
239\&\fIBIO_seek()\fR, but this may still succeed if the chain ends in a \s-1FILE\s0
240or file descriptor \s-1BIO\s0.
241.PP
242Source/sink BIOs return an 0 if they do not recognize the \fIBIO_ctrl()\fR
243operation.
244.SH "BUGS"
245.IX Header "BUGS"
246Some of the return values are ambiguous and care should be taken. In
247particular a return value of 0 can be returned if an operation is not
248supported, if an error occurred, if \s-1EOF\s0 has not been reached and in
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258the case of \fIBIO_seek()\fR on a file \s-1BIO\s0 for a successful operation.
| 249the case of \fIBIO_seek()\fR on a file \s-1BIO\s0 for a successful operation.
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259.SH "SEE ALSO"
260.IX Header "SEE ALSO"
261\&\s-1TBA\s0
| 250.SH "SEE ALSO"
251.IX Header "SEE ALSO"
252\&\s-1TBA\s0
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