no it doesn't:

open to write (will overwrite the file)
int $fileid = `fopen $filename "w"`;

open to append to the file
int $fileid = `fopen $filename "a"`;

//from the docs
"w" open file for writing (destroys prior contents of file).
"a" append for writing (appends to end of file).
"r" open for reading.



Alan