X-Git-Url: https://code.wpia.club/?a=blobdiff_plain;f=lib%2Fopenssl%2Fdoc%2Fcrypto%2FBIO_ctrl.pod;fp=lib%2Fopenssl%2Fdoc%2Fcrypto%2FBIO_ctrl.pod;h=722e8b8f46c9c5b202bb4283338e7411d582f2d7;hb=9ff1530871deeb0f7eaa35ca0db6630724045e4a;hp=0000000000000000000000000000000000000000;hpb=25b73076b01ae059da1a2e9a1677e00788ada620;p=cassiopeia.git diff --git a/lib/openssl/doc/crypto/BIO_ctrl.pod b/lib/openssl/doc/crypto/BIO_ctrl.pod new file mode 100644 index 0000000..722e8b8 --- /dev/null +++ b/lib/openssl/doc/crypto/BIO_ctrl.pod @@ -0,0 +1,128 @@ +=pod + +=head1 NAME + +BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset, +BIO_seek, BIO_tell, BIO_flush, BIO_eof, BIO_set_close, BIO_get_close, +BIO_pending, BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending, +BIO_get_info_callback, BIO_set_info_callback - BIO control operations + +=head1 SYNOPSIS + + #include + + long BIO_ctrl(BIO *bp,int cmd,long larg,void *parg); + long BIO_callback_ctrl(BIO *b, int cmd, void (*fp)(struct bio_st *, int, const char *, int, long, long)); + char * BIO_ptr_ctrl(BIO *bp,int cmd,long larg); + long BIO_int_ctrl(BIO *bp,int cmd,long larg,int iarg); + + int BIO_reset(BIO *b); + int BIO_seek(BIO *b, int ofs); + int BIO_tell(BIO *b); + int BIO_flush(BIO *b); + int BIO_eof(BIO *b); + int BIO_set_close(BIO *b,long flag); + int BIO_get_close(BIO *b); + int BIO_pending(BIO *b); + int BIO_wpending(BIO *b); + size_t BIO_ctrl_pending(BIO *b); + size_t BIO_ctrl_wpending(BIO *b); + + int BIO_get_info_callback(BIO *b,bio_info_cb **cbp); + int BIO_set_info_callback(BIO *b,bio_info_cb *cb); + + typedef void bio_info_cb(BIO *b, int oper, const char *ptr, int arg1, long arg2, long arg3); + +=head1 DESCRIPTION + +BIO_ctrl(), BIO_callback_ctrl(), BIO_ptr_ctrl() and BIO_int_ctrl() +are BIO "control" operations taking arguments of various types. +These functions are not normally called directly, various macros +are used instead. The standard macros are described below, macros +specific to a particular type of BIO are described in the specific +BIOs manual page as well as any special features of the standard +calls. + +BIO_reset() typically resets a BIO to some initial state, in the case +of file related BIOs for example it rewinds the file pointer to the +start of the file. + +BIO_seek() resets a file related BIO's (that is file descriptor and +FILE BIOs) file position pointer to B bytes from start of file. + +BIO_tell() returns the current file position of a file related BIO. + +BIO_flush() normally writes out any internally buffered data, in some +cases it is used to signal EOF and that no more data will be written. + +BIO_eof() returns 1 if the BIO has read EOF, the precise meaning of +"EOF" varies according to the BIO type. + +BIO_set_close() sets the BIO B close flag to B. B can +take the value BIO_CLOSE or BIO_NOCLOSE. Typically BIO_CLOSE is used +in a source/sink BIO to indicate that the underlying I/O stream should +be closed when the BIO is freed. + +BIO_get_close() returns the BIOs close flag. + +BIO_pending(), BIO_ctrl_pending(), BIO_wpending() and BIO_ctrl_wpending() +return the number of pending characters in the BIOs read and write buffers. +Not all BIOs support these calls. BIO_ctrl_pending() and BIO_ctrl_wpending() +return a size_t type and are functions, BIO_pending() and BIO_wpending() are +macros which call BIO_ctrl(). + +=head1 RETURN VALUES + +BIO_reset() normally returns 1 for success and 0 or -1 for failure. File +BIOs are an exception, they return 0 for success and -1 for failure. + +BIO_seek() and BIO_tell() both return the current file position on success +and -1 for failure, except file BIOs which for BIO_seek() always return 0 +for success and -1 for failure. + +BIO_flush() returns 1 for success and 0 or -1 for failure. + +BIO_eof() returns 1 if EOF has been reached 0 otherwise. + +BIO_set_close() always returns 1. + +BIO_get_close() returns the close flag value: BIO_CLOSE or BIO_NOCLOSE. + +BIO_pending(), BIO_ctrl_pending(), BIO_wpending() and BIO_ctrl_wpending() +return the amount of pending data. + +=head1 NOTES + +BIO_flush(), because it can write data may return 0 or -1 indicating +that the call should be retried later in a similar manner to BIO_write(). +The BIO_should_retry() call should be used and appropriate action taken +is the call fails. + +The return values of BIO_pending() and BIO_wpending() may not reliably +determine the amount of pending data in all cases. For example in the +case of a file BIO some data may be available in the FILE structures +internal buffers but it is not possible to determine this in a +portably way. For other types of BIO they may not be supported. + +Filter BIOs if they do not internally handle a particular BIO_ctrl() +operation usually pass the operation to the next BIO in the chain. +This often means there is no need to locate the required BIO for +a particular operation, it can be called on a chain and it will +be automatically passed to the relevant BIO. However this can cause +unexpected results: for example no current filter BIOs implement +BIO_seek(), but this may still succeed if the chain ends in a FILE +or file descriptor BIO. + +Source/sink BIOs return an 0 if they do not recognize the BIO_ctrl() +operation. + +=head1 BUGS + +Some of the return values are ambiguous and care should be taken. In +particular a return value of 0 can be returned if an operation is not +supported, if an error occurred, if EOF has not been reached and in +the case of BIO_seek() on a file BIO for a successful operation. + +=head1 SEE ALSO + +TBA