overwriting a part of a text file?

[Thijs Boeree]

Hi, i am writing an application where i can set markers on a waveform graph,
now i want to write the values of the markers in a text-based file
(spreadsheet) I make one file with several markers, but it happens that i
want to overwrite a part of the text file, where a marker is, does anyone
knows how to overwrite a part of a text file, with a VI with inputs of an
offset and a length?

Best regards,
Thijs

[JeanPierre]

The "Write File" function has an offset input. The lenght written is the length of the data on input. First you open the file giving its path to "Open File", you write data at offset and "Close File". The previous content of the file at offset is overwritten.