Prosoft-technology MVI69-ADM Bedienungsanleitung PDF herunterladen (Seite 262)

Serial Port Library Functions MVI-ADM ♦ 'C' Programmable

Developer's Guide 'C' Programmable Application Development Module

Page 262 of 342 ProSoft Technology, Inc.

February 20, 2013

MVIsp_GetCountUnread

Syntax

int MVIsp_GetCountUnread(int comport, int *count);

Parameters

comport

Desired communications port

count

Pointer to int to receive unread character count

Description

MVIsp_GetCountUnread returns the number of characters in the receive queue

that are waiting to be read. Since data received from a port is queued after

reception from a serial port, the application may need to determine if all

characters have been read or how many characters remain to be read.

comport is the desired serial port and must be previously opened with

MVIsp_Open.

count points to an int that will receive the number of characters that have been

received from the serial port but not read by the application. If the returned count

is 0, all received data has been read. If it is non-zero, it contains the number of

characters placed into the receive queue after reception from a serial port but

that have not been read from the queue with MVIsp_Getch, MVIsp_Gets, or

MVIsp_GetData.

Return Value

MVI_SUCCESS

count retrieved successfully

MVI_ERR_NOACCESS

comport has not been opened

MVI_ERR_BADPARAM

invalid pointer

Example

int count;

if (MVIsp_GetCountUnread(COM2,&count) == MVI_SUCCESS)

{

if (count == 0)

printf("All chars read\n");

else

printf("%d characters remaining\n",count);

}

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Prosoft-technology MVI69-ADM Bedienungsanleitung Seite 262