[Bug stdio/28932] New: scanf "%n" incorrectly requires int pointer, instead of size_t pointer

[Bug stdio/28932] New: scanf "%n" incorrectly requires int pointer, instead of size_t pointer

[john.m.kenny at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=28932

            Bug ID: 28932
           Summary: scanf "%n" incorrectly requires int pointer, instead
                    of size_t pointer
           Product: glibc
           Version: unspecified
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: stdio
          Assignee: unassigned at sourceware dot org
          Reporter: john.m.kenny at outlook dot com
  Target Milestone: ---

The scanf function's conversion specifier "%n" requires the next pointer to be
a pointer to an int. That int gets "the  number of characters consumed thus far
from the input". However, an int may not be large enough to read the number of
chars read.

Previous programmers have identified this issue and resolved it by using a
size_t. As evidence, the strlen(3) function returns a size_t and not an int.

The fix: make the require pointer for the "%n" conversion specifier a size_t
pointer instead of an int.

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[Bug stdio/28932] scanf "%n" incorrectly requires int pointer, instead of size_t pointer

[schwab@linux-m68k.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=28932

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |NOTABUG
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
If you want to store a size_t, use %zn.

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