Read data from device asynchronously. Parameters Name Direction Type Description vi ViSession IN Unique logical identifier to a session. buf OUT ViBuf Represents the location of a buffer to receive data from device. count IN ViUInt32 Number of bytes to be read. jobId OUT ViJobId Represents the location of a variable that will be set to the job identifier of this asynchronous read operation. Return Values Type This is the operational return status. It returns either a ViStatus completion code or an error code as follows. Completion Codes Description VI_SUCCESS Asynchronous read operation successfully queued. VI_SUCCESS_SYNC Read operation performed synchronously. Error Codes Description VI_ERROR_INV_SESSION The given session or object reference is invalid (both VI_ERROR_INV_OBJECT are the same value). VI_ERROR_RSRC_LOCKED Specified operation could not be performed because the resource identified by has been locked for this vi kind of access. VI_ERROR_QUEUE_ERROR Unable to queue read operation. VI_ERROR_IN_PROGRESS Unable to start a new asynchronous operation while another asynchronous operation is in progress. Description The asynchronous read operation asynchronously transfers data. The data read is to be stored in the buffer represented by This operation normally returns before the transfer terminates. An I/O Completion buf. event will be posted when the transfer is actually completed. The operation returns which you can use with either to abort the operation or jobId, viTerminate() with an I/O Completion event to identify which asynchronous read operation completed. Table 6.1.2 Special Values for Parameter jobId Value Action Description VI_NULL Do not return a job identifier. Related Items
Read data from device asynchronously. Parameters Name Direction Type Description vi IN ViSession Unique logical identifier to a session. buf OUT ViBuf Represents the location of a buffer to receive data from device. count IN ViUInt32 Number of bytes to be read. jobId OUT ViJobId Represents the location of a variable that will be set to the job identifier of this asynchronous read operation. Return Values Type ViStatus This is the operational return status. It returns either a completion code or an error code as follows. Completion Codes Description VI_SUCCESS Asynchronous read operation successfully queued. VI_SUCCESS_SYNC Read operation performed synchronously. Error Codes Description VI_ERROR_INV_SESSION VI_ERROR_INV_OBJECT The given session or object reference is invalid (both are the same value). VI_ERROR_RSRC_LOCKED Specified operation could not be performed because the resource identified by vi has been locked for this kind of access. VI_ERROR_QUEUE_ERROR Unable to queue read operation. VI_ERROR_IN_PROGRESS Unable to start a new asynchronous operation while another asynchronous operation is in progress. Description The asynchronous read operation asynchronously transfers data. The data read is to be stored in the buffer represented by buf. This operation normally returns before the transfer terminates. An I/O Completion event will be posted when the transfer is actually completed. The operation returns jobId, which you can use with either viTerminate() to abort the operation or with an I/O Completion event to identify which asynchronous read operation completed. Table 6.1.2 Special Values for jobId Parameter Value Action Description VI_NULL Do not return a job identifier. Related Items
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