[Bug c++/38980] New: missing -Wformat warning on const char format string

[sebor at roguewave dot com]

When compiled with gcc 3.4.6 with -m32 on x86_64 Linux the compiler flags lines
7, 10, and 13 as expected. But when compiled with gcc 4.3.1, only line 7 is
diagnosed.

$ cat -n t.cpp && g++ -dumpversion && g++ -Wformat -m32 -c t.cpp
     1  #include <stdio.h>
     2
     3  void foo (size_t n)
     4  {
     5      char buf [32];
     6
     7      sprintf (buf, "%" "l" "u", n);
     8
     9      static const char fmt0[] = "%" "l" "u";
    10      sprintf (buf, fmt0, n);
    11
    12      const char fmt1[] = "%" "l" "u";
    13      sprintf (buf, fmt1, n);
    14
    15      static char fmt2[] = "%" "l" "u";
    16      sprintf (buf, fmt2, n);
    17
    18      char fmt3[] = "%" "l" "u";
    19      sprintf (buf, fmt3, n);
    20  }
3.4.6
t.cpp: In function `void foo(size_t)':
t.cpp:7: warning: long unsigned int format, size_t arg (arg 3)
t.cpp:10: warning: long unsigned int format, size_t arg (arg 3)
t.cpp:13: warning: long unsigned int format, size_t arg (arg 3)
$
$ g++ -dumpversion && g++ -Wformat -m32 -c  t.cpp
4.3.1
t.cpp: In function 'void foo(size_t)':
t.cpp:7: warning: format '%lu' expects type 'long unsigned int', but argument 3
has type 'size_t'
$


-- 
           Summary: missing -Wformat warning on const char format string
           Product: gcc
           Version: 4.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sebor at roguewave dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38980