User`s guide

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);