Defect Report #143
Submission Date: 23 Feb 95
Source: Clive D.W. Feather
Submitted to BSI by Clive D.W. Feather firstname.lastname@example.org.
In this Defect Report, identifiers lexically identical to those
declared in standard headers refer to the identifiers declared in those
standard headers, whether or not the header is explicitly mentioned.
This Defect Report has been prepared with considerable help from
Mark Brader, Jutta Degener, Ronald Guilmette, and a person whose
employment conditions require anonymity. However, except where stated,
opinions expressed or implied should not be assumed to be those of any
person other than myself.
Defect Report UK 027: fopen modes
[BSI characterize this issue as minor.]
The definition of file opening modes is self-contradictory.
Subclause 18.104.22.168 reads in part:
The argument mode points to a string beginning with one of the
and then lists all of r, r+,
rb, and rb+ or
r+b, with different meanings. Obviously, it is
possible for a string to begin with up to three of these
simultaneously, and thus the quoted text is contradictory.
Also, the wording is confusing since it can easily be misread as
"beginning with exactly one of the following sequences," which would
prohibit those of the specified modes that are longer than one
Suggested Technical Corrigendum:
Change the quoted text to:
The mode is determined by the longest match of the following
sequences to the initial characters of the string pointed to by the
argument mode; at least the initial character shall
Suggested Future Change
The current C Standard has correct meaning, but the wording could
be clearer. We suggest the following change for the revised C Standard:
The argument mode points to a string. The mode
is determined by the string's longest initial match to the following
sequences; at least the initial character shall match:
Previous Defect Report
< - >
Next Defect Report