diff options
author | Dr. Stephen Henson <steve@openssl.org> | 2000-09-12 01:56:56 +0000 |
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committer | Dr. Stephen Henson <steve@openssl.org> | 2000-09-12 01:56:56 +0000 |
commit | d572cb6c1c95c1371b9c1eb986d4736c53fa9f40 (patch) | |
tree | fda51fbe0fe79d67f5ee3d06672cb79f36fea51e /doc/crypto/BIO_ctrl.pod | |
parent | 05c2b37176e15f86f2ca2f96745f5258aa9b1192 (diff) |
More BIO docs.
Diffstat (limited to 'doc/crypto/BIO_ctrl.pod')
-rw-r--r-- | doc/crypto/BIO_ctrl.pod | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/doc/crypto/BIO_ctrl.pod b/doc/crypto/BIO_ctrl.pod new file mode 100644 index 0000000000..dfec019614 --- /dev/null +++ b/doc/crypto/BIO_ctrl.pod @@ -0,0 +1,93 @@ +=pod + +=head1 NAME + + BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl - BIO control operations + +=head1 SYNOPSIS + + #include <openssl/bio.h> + + 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_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 reset a BIO to some initial state, in the case +of file related BIOs for example it rewinds the file pointer. + +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<b> close flag to B<flag>. B<flag> 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 characterers 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() returns 1 fo success and 0 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. + +=head1 SEE ALSO + +TBA |