Cogent C API and Utilities :  Version 7.2
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IP_Receive

IP_Receive — receives any message.

Syntax

#include <cogent.h>
int IP_Receive(IP_Task*  myself, 
 IP_Msg*  rmsg, 
 IP_MsgInfo*  msginfo);

Arguments

myself
A task structure referring to the current process.
rmsg
A message structure to hold the received message.
msginfo
A structure to be filled with extra information.

Returns

The type of the received message.

Description

This function receives message of any form, and classifies them according to type. Relevant information about the sender is stored in the msginfo structure. A message can be one of the following types:

  • IP_GUI means a GUI event occurred. No further processing is necessary.

  • IP_ASYNC means an asynchronous message was received. No reply is necessary.

    • msginfo->subtype = ST_DH_EXCEPTION, ST_DH_ECHO, or other.
    • msginfo->rcvid = the queue pulse ID

  • IP_SYNC means a synchronous message was received. A reply is necessary via a call to IP_MsgInfoReply.

    • msginfo->rcvid = the rcvid (QNX 6) or the pid (QNX 4/Linux)
  • IP_NONE means IP_Receive returned without receiving a message. This is possible if the queue pulse is triggered, but the queued message is no longer available.

  • IP_ERROR means an error occurred during IP_Receive, but defied classification.

    • msginfo->rcvid = errno
  • IP_SIGNAL means IP_Receive exited due to a signal.

  • IP_PULSE means a pulse was received. No reply is necessary.

    • msginfo->rcvid = the pulse ID.

  • IP_RAW means a message from a task not using the Cascade IPC library was received. The message data is contained in (void*)(rmsg->msg). A reply is required with a call to IP_MsgInfoReplyRaw.

    • msginfo->rcvid = the rcvid (QNX 6) or the pid (QNX 4/Linux)

  • IP_FD means activity occurred on a file descriptor. No data has been read from the file descriptor.

    • msginfo->rcvid = the file descriptor.

See Also

Receiving Messages and Events, IP_ReceiveNonblock

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