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<== Date ==> <== Thread ==>
Subject: Bug in Asyn 4-23 drvAsynUSBTMC (with patch)
From: Bruno Martins <[email protected]>
To: "[email protected]" <[email protected]>
Date: Wed, 19 Nov 2014 13:53:11 -0500
Hi all,

I'm using drvAsynUSBTMC to talk to a Tektronix scope and found a bug.

asynOctetRead (in drvAsynUSBTMC.c) tries to fill the passed 'data' pointer with data from 'pdpvt->bufp'. However, if 'maxchars' > 'pdpvt->bufCount'  a new packet will be requested from the USB driver and be saved to 'pdpvt->bufp'. Then, in the next 'for' loop iteration, 'data' will be overwritten.

The fix is to increment 'data' pointer by the appropriate amount. A patch is attached.



Thanks,

Bruno
diff --git a/asyn/drvAsynUSBTMC/drvAsynUSBTMC.c b/asyn/drvAsynUSBTMC/drvAsynUSBTMC.c
index 678fc3c..fca9f56 100644
--- a/asyn/drvAsynUSBTMC/drvAsynUSBTMC.c
+++ b/asyn/drvAsynUSBTMC/drvAsynUSBTMC.c
@@ -798,6 +798,7 @@ asynOctetRead(void *pvt, asynUser *pasynUser,
             maxchars -= nCopy;
             *nbytesTransfered += nCopy;
             pdpvt->bytesReceivedCount += nCopy;
+            data += nCopy;
             if (maxchars == 0)
                 eom |= ASYN_EOM_CNT;
         }
Replies:
Re: Bug in Asyn 4-23 drvAsynUSBTMC (with patch) Eric Norum
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