>How can i assure that fputs or fwrite writes a single line of text and the text file contains one single line of text too?
>

FPUTS() adds a newline to the end-of-line, FWRITE() does not. If you need to write part of a line, planning to write more to the same line, use FWRITE() to write to the file. You can always add a newline (CHR(13)+CHR(10)) to the next FWRITE() to start on the next line.

If you never put a newline character in the text, it's only one line; you may find that if you try to send that to a printer, either Windows or the printer itself may force the line to split; that's an issue with your printer driver or the printer itself. If viewed in a WinApp such as Notepad or Wordpad, they may turn on word-wrap. None of these is controlled with VFP.