fopen ( ..., "a" ) --- how does the "a" work?

[Doug Gwyn]

In article <1890 at crdos1.crd.ge.COM> davidsen at crdos1.crd.ge.COM (Wm E Davidsen Jr) writes:
-  In retrospect I think that one more key letter would have been useful
-in pANS. The use of "a" to mean 'always append, never rewrite' is a
-useful one, but often "a" is used when what is meant is to 'open the
-existing file if there is one, otherwise create one.'

If so, that's simply a user error.  That is not and never has been
the meaning of the "a" fopen() mode.