text: NAME
  BIO_should_read, BIO_should_write, BIO_should_io_special, BIO_retry_type, BIO_should_retry, BIO_get_retry_BIO, BIO_get_retry_reason, BIO_set_retry_reason - BIO retry functions
  SYNOPSIS
  #include <openssl/bio.h> int BIO_should_read(BIO *b); int BIO_should_write(BIO *b); int BIO_should_io_special(iBIO *b); int BIO_retry_type(BIO *b); int BIO_should_retry(BIO *b); BIO *BIO_get_retry_BIO(BIO *bio, int *reason); int BIO_get_retry_reason(BIO *bio); void BIO_set_retry_reason(BIO *bio, int reason);
  DESCRIPTION
  These functions determine why a BIO is not able to read or write data. They will typically be called after a failed BIO_read_ex() or BIO_write_ex() the BIO has insufficient data to return. Check for readability and/or retry the last operation.
  BIO_should_write() is true if the cause of the condition is that the BIO has pending data to write. Check for writability and/or retry the last operation.,().
  BIO_set_retry_reason() sets the retry reason for a special condition for a given BIO. This would usually only be called by BIO implementations.
  NOTES
  BIO_should_read(), BIO_should_write(), BIO_should_io_special(), BIO_retry_type(), and BIO_should_retry(), are implemented as macros.
  If BIO_should_retry() returns false then the precise "error condition" depends on the BIO type that caused it and the return code of the BIO operation. For example if a call to BIO_read_ex() on a socket BIO returns 0 and BIO_should_retry() is false then the cause will be that the connection functions when the entire structure can be read or written.
  RETURN VALUES
  BIO_should_read(), BIO_should_write(), BIO_should_io_special(), and BIO_should_retry() return either 1 or 0 based on the actual conditions of the BIO.
  BIO_retry_type() returns a flag combination presenting the cause of a retry condition or false if there is no retry condition.
  BIO_get_retry_BIO() returns a valid BIO structure.
  BIO_get_retry_reason() returns the reason for a special condition.
  SEE ALSO
  HISTORY
  The BIO_get_retry_reason() and BIO_set_retry_reason() functions were added in OpenSSL 1.1.0.
  Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at.