ACE/ace/FIFO_Recv_Msg.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    FIFO_Recv_Msg.h
   6  *
   7  *  @author Doug Schmidt
   8  */
   9 //=============================================================================
  10
  11
  12 #ifndef ACE_FIFO_RECV_MSG_H
  13 #define ACE_FIFO_RECV_MSG_H
  14 #include /**/ "ace/pre.h"
  15
  16 #include "ace/FIFO_Recv.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  23
  24 // Forward decls
  25 class ACE_Str_Buf;
  26
  27 /**
  28  * @class ACE_FIFO_Recv_Msg
  29  *
  30  * @brief Receiver side for the record oriented C++ wrapper for UNIX FIFOs.
  31  *
  32  * This method works slightly differently on platforms with the
  33  * @c ACE_HAS_STREAM_PIPES configuration setting than those without.
  34  * With ACE_HAS_STREAM_PIPES, the @c getmsg() system function is used
  35  * and it preserves message boundaries internally. Without
  36  * @c ACE_HAS_STREAM_PIPES, the message boundaries are emulated by
  37  * this class and ACE_FIFO_Send_Msg cooperating. The sending class
  38  * first writes an integer number of bytes in the message, then the
  39  * message. ACE_FIFO_Recv_Msg reads the count, then the data.
  40  * The operational differences occur primarily when a message is larger
  41  * than what a caller of this class requests. See recv() for details.
  42  */
  43 class ACE_Export ACE_FIFO_Recv_Msg : public ACE_FIFO_Recv
  44 {
  45 public:
  46   /// Default constructor.
  47   ACE_FIFO_Recv_Msg ();
  48
  49   /// Open up a record-oriented named pipe for reading.
  50   ACE_FIFO_Recv_Msg (const ACE_TCHAR *rendezvous,
  51                      int flags = O_CREAT | O_RDONLY,
  52                      mode_t perms = ACE_DEFAULT_FILE_PERMS,
  53                      int persistent = 1,
  54                      LPSECURITY_ATTRIBUTES sa = 0);
  55
  56   /// Open up a record-oriented named pipe for reading.
  57   int open (const ACE_TCHAR *rendezvous,
  58             int flags = O_CREAT | O_RDONLY,
  59             mode_t perms = ACE_DEFAULT_FILE_PERMS,
  60             int persistent = 1,
  61             LPSECURITY_ATTRIBUTES sa = 0);
  62
  63   /// Receive a message based on attributes in an ACE_Str_Buf.
  64   /**
  65    * @param msg  Reference to an ACE_Str_Buf whose @c buf member points
  66    *             to the memory to receive the data and @c maxlen member
  67    *             contains the maximum number of bytes to receive.
  68    *             On return after successfully reading data, the
  69    *             @c len member contains the number of bytes received and
  70    *             placed in the buffer pointed to by @c msg.buf.
  71    *
  72    * @retval -1  Error; consult @c errno for specific error number.
  73    * @return     If the @c ACE_HAS_STREAM_PIPES configuration setting is
  74    *             defined, the return value is the number of bytes received
  75    *             in the message and will be the same as @c buf.len.
  76    *             The return value from the @c getmsg() system function
  77    *             is discarded.
  78    *             If @c ACE_HAS_STREAM_PIPES is not defined, the number
  79    *             of bytes in the message read from the FIFO is returned.
  80    *             If the message is larger than the maximum length
  81    *             requested in @c msg.maxlen, the return value reflects
  82    *             the entire message length, and the @c msg.len member
  83    *             reflects how many bytes were actually placed in the
  84    *             caller's buffer. Any part of the message longer than
  85    *             @c msg.maxlen is discarded.
  86    */
  87   ssize_t recv (ACE_Str_Buf &msg);
  88
  89   /// Receive a message based on buffer pointer and maximum size.
  90   /**
  91    * @param buf  Pointer to the memory to receive the data.
  92    * @param len  The maximum number of bytes to receive.
  93    *
  94    * @retval -1  Error; consult @c errno for specific error number.
  95    * @return     The number of bytes received in the message. For messages
  96    *             that are larger than the requested maximum size, the
  97    *             behavior is different depending on the @c ACE_HAS_STREAM_PIPES
  98    *             configuration setting. With @c ACE_HAS_STREAM_PIPES,
  99    *             the return value will be the same as @arg len (this is
 100    *             also possible if the message is exactly the same length
 101    *             as @arg len, and the two cases are indistinguishable).
 102    *             Without @c ACE_HAS_STREAM_PIPES, the return value is
 103    *             the total length of the message, including bytes in
 104    *             excess of @arg len. The excess bytes are discarded.
 105    */
 106   ssize_t recv (void *buf, size_t len);
 107
 108 #if defined (ACE_HAS_STREAM_PIPES)
 109   /// Recv @a data and @a cntl message via Stream pipes.
 110   ssize_t recv (ACE_Str_Buf *data,
 111                 ACE_Str_Buf *cntl,
 112                 int *flags);
 113
 114   /// Recv @a data and @a cntl message via Stream pipes in "band" mode.
 115   ssize_t recv (int *band,
 116                 ACE_Str_Buf *data,
 117                 ACE_Str_Buf *cntl,
 118                 int *flags);
 119 #endif /* ACE_HAS_STREAM_PIPES */
 120
 121   /// Dump the state of an object.
 122   void dump () const;
 123
 124   /// Declare the dynamic allocation hooks.
 125   ACE_ALLOC_HOOK_DECLARE;
 126 };
 127
 128 ACE_END_VERSIONED_NAMESPACE_DECL
 129
 130 #if defined (__ACE_INLINE__)
 131 #include "ace/FIFO_Recv_Msg.inl"
 132 #endif /* __ACE_INLINE__ */
 133
 134 #include /**/ "ace/post.h"
 135 #endif /* ACE_FIFO_RECV_MSG_H */