Agilent Technologies E2094S, User Manual, Page: 41 / 146

Programming with VISA
3
Agilent VISA User’s Guide 41
Using Formatted I/O
As noted, the VISA formatted I/O functions are viPrintf , viQueryf , and
viScanf
.
• viPrintf formats data according to the format string ( writeFmt ) and
sends the data to a device. viPrintf sends separate arg parameters,
while the viVPrintf function sends a list of parameters in params :
viPrintf( vi , writeFmt [, arg1 ][, arg2 ][, ...]);
viVPrintf( vi , writeFmt , params );
• viScanf receives and converts data from a device according to the
format string ( readFmt ). The viScanf function receives separate arg
parameters, while the viVScanf function receives a list of parameters
in params :
viScanf( vi , readFmt [, arg1 ][, arg2 ][, ...]);
viVScanf( vi , readFmt , params );
• viQueryf formats and sends data to a device and then immediately
receives and converts the response data. Hence, viQueryf is a
combination of both viPrintf and viScanf functions. Similarly,
viVQueryf is a combination of viVPrintf and viVScanf . viQueryf
sends and receives separate arg parameters, while the viVQueryf
function sends and receives a list of parameters in params :
viQueryf( vi , writeFmt , readFmt [, arg1 ]
[, arg2 ][, ...]);
viVQueryf( vi , writeFmt , readFmt , params );
Formatted I/O Conversion
Formatted I/O functions convert data under the control of the format
specifier. The format specifier consists of a
%
(percent) symbol, optional
modifier, and a format code. Both readFmt and writeFmt have the form:
%[modifier]formatCode
Example: Receiving Data From a Session The following example
uses viScanf to receive data from the session specified by the vi
parameter and converts the data to a string.
char data[180];
viScanf(vi, "%t", data);