fwrite() and length of string problem

[nescio]

hello,

i have information (string) in a variable.
i write the variable to a csv-file.
all of the information in the varaible must appear on one line.
so when i write ten variables to the csv-file i must have ten lines;

some string a very long and some are very short.

the problem is: sometimes a string appears on two lines, instead of one.
as if there is a break;

how is this possible?

i do not control the value of the variable, because it comes from a database
that clients fill.

my question is:
- is there a maximum that a line accepts, and when there is more information
than the maximum allows it
starts a new line?
- how do i get al of the information of a varaible on one line?

thanks