A format string consists of one or more format specifications that tell PV-WAVE what types of data are being handled and how to format the data. For example, a C format string for importing data might look like this:

%3d %f

This string contains two format specifications. The first one (%3d) transfers signed integer data, with a maximum field width of three spaces. The second specification (%f) transfers floating-point data, with no specified field width. This format string might be used to read a data file containing two columns of numbers, one column containing integers and the other floating-point numbers.