BIO_gets(3)

     BIO_read(3)            0.9.6h (2000-09-16)            BIO_read(3)

     NAME
          BIO_read, BIO_write, BIO_gets, BIO_puts - BIO I/O functions

     SYNOPSIS
           #include <openssl/bio.h>

           int    BIO_read(BIO *b, void *buf, int len);
           int    BIO_gets(BIO *b,char *buf, int size);
           int    BIO_write(BIO *b, const void *buf, int len);
           int    BIO_puts(BIO *b,const char *buf);

     DESCRIPTION
          BIO_read() attempts to read len bytes from BIO b and places
          the data in buf.

          BIO_gets() performs the BIOs "gets" operation and places the
          data in buf. Usually this operation will attempt to read a
          line of data from the BIO of maximum length len. There are
          exceptions to this however, for example BIO_gets() on a
          digest BIO will calculate and return the digest and other
          BIOs may not support BIO_gets() at all.

          BIO_write() attempts to write len bytes from buf to BIO b.

          BIO_puts() attempts to write a null terminated string buf to
          BIO b

     RETURN VALUES
          All these functions return either the amount of data
          successfully read or written (if the return value is
          positive) or that no data was successfully read or written
          if the result is 0 or -1. If the return value is -2 then the
          operation is not implemented in the specific BIO type.

     NOTES
          A 0 or -1 return is not necessarily an indication of an
          error. In particular when the source/sink is non-blocking or
          of a certain type it may merely be an indication that no
          data is currently available and that the application should
          retry the operation later.

          One technique sometimes used with blocking sockets is to use
          a system call (such as select(), poll() or equivalent) to
          determine when data is available and then call read() to
          read the data. The equivalent with BIOs (that is call
          select() on the underlying I/O structure and then call
          BIO_read() to read the data) should not be used because a
          single call to BIO_read() can cause several reads (and
          writes in the case of SSL BIOs) on the underlying I/O
          structure and may block as a result. Instead select() (or
          equivalent) should be combined with non blocking I/O so
          successive reads will request a retry instead of blocking.

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     BIO_read(3)            0.9.6h (2000-09-16)            BIO_read(3)

          See BIO_should_retry(3) for details of how to determine the
          cause of a retry and other I/O issues.

          If the BIO_gets() function is not supported by a BIO then it
          possible to work around this by adding a buffering BIO
          BIO_f_buffer(3) to the chain.

     SEE ALSO
          BIO_should_retry(3)

          TBA

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