MC_FLUSH
The MC_FLUSH verb sends the contents of the local LU's send buffer to the partner LU (and TP). If the send buffer is empty, no action takes place.
For the Microsoft® Windows® version 3.x system, it is recommended that you use WinAsyncAPPC rather than the blocking version of this call.
The following structure describes the verb control block used by the MC_FLUSH verb.
struct mc_flush {
unsigned short opcode;
unsigned char opext;
unsigned char reserv2;
unsigned short primary_rc;
unsigned long secondary_rc;
unsigned char tp_id[8];
unsigned long conv_id;
};
Members
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opcode
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Supplied parameter. Specifies the verb operation code, AP_M_FLUSH.
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opext
-
Supplied parameter. Specifies the verb operation extension, AP_MAPPED_CONVERSATION.
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primary_rc
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Returned parameter. Specifies the primary return code set by APPC at the completion of the verb. The valid return codes vary depending on the APPC verb issued. See Return Codes for valid error codes for this verb.
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secondary_rc
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Returned parameter. Specifies the secondary return code set by APPC at the completion of the verb. The valid return codes vary depending on the APPC verb issued. See Return Codes for valid error codes for this verb.
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tp_id
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Supplied parameter. Identifies the local TP. The value of this parameter is returned by TP_STARTED in the invoking TP or by RECEIVE_ALLOCATE in the invoked TP.
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conv_id
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Supplied parameter. Provides the conversation identifier. The value of this parameter is returned by MC_ALLOCATE in the invoking TP or by RECEIVE_ALLOCATE in the invoked TP.
Return Codes
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ap_ok
-
Primary return code; the verb executed successfully.
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ap_parameter_check
-
Primary return code; the verb did not execute because of a parameter error.
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ap_bad_conv_id
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Secondary return code; the value of conv_id did not match a conversation identifier assigned by APPC.
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ap_bad_tp_id
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Secondary return code; the value of tp_id did not match a TP identifier assigned by APPC.
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ap_state_check
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Primary return code; the verb did not execute because it was issued in an invalid state.
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ap_flush_not_send_state
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Secondary return code; the conversation was not in SEND state.
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ap_comm_subsystem_abended
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Primary return code; indicates one of the following conditions:
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The node used by this conversation encountered an ABEND.
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The connection between the TP and the PU 2.1 node has been broken (a LAN error).
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The SnaBase at the TP's computer encountered an ABEND.
The system administrator should examine the error log to determine the reason for the ABEND.
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ap_conversation_type_mixed
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Primary return code; the TP has issued both basic and mapped conversation verbs. Only one type can be issued in a single conversation.
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ap_invalid_verb_segment
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Primary return code; the VCB extended beyond the end of the data segment.
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ap_stack_too_small
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Primary return code; the stack size of the application is too small to execute the verb. Increase the stack size of your application.
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ap_conv_busy
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Primary return code; there can only be one outstanding conversation verb at a time on any conversation. This can occur if the local TP has multiple threads, and more than one thread is issuing APPC calls using the same conv_id.
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ap_unexpected_dos_error
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Primary return code; the operating system has returned an error to APPC while processing an APPC call from the local TP. The operating system return code is returned through the secondary_rc. It appears in Intel byte-swapped order. If the problem persists, consult the system administrator.
Remarks
Data processed by MC_SEND_DATA accumulates in the local LU's send buffer until one of the following happens:
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The local TP issues MC_FLUSH (or other verb that flushes the LU's send buffer).
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The buffer is full.
The request generated by MC_ALLOCATE is also buffered.
The conversation must be in SEND state when the TP issues this verb.
There is no state change.