Currently the -Wmissing-format-attribute works on functions by examining the
current function body for calls to vprintf-like functions and if so it flags
the current function as a candidate for another format attribute. You can then
back-track to callees and propagate the attribute as necessary by recompiling
the code with the new attribute added. This works fine for functions, but
doesn't pick up function pointers. For example:
#include <stdio.h>
int (*ptr)(const char *, ...);
int main()
{
ptr = printf;
ptr("hello world %d\n", 5L);
return 0;
}
This code compiled with -Wall -Wmissing-format-attribute doesn't yield any
warnings because there's no format attribute on the function pointer 'ptr' to
complain about the int vs. long mismatch, and the missing format attribute
detection doesn't catch that that the attribute is missing.
However in the assignment 'ptr = printf' we should be able to detect that both
operands are indeed variable argument functions (or function pointers) and that
the right-hand side has a format attribute whereas the left-hand side doesn't.
This should trigger the missing format attribute diagnostic.
Beyond printf, we should do the same for vprintf-like functions as well.
--
Summary: -Wmissing-format-attribute should pick out function
pointer candidates also
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: enhancement
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: ghazi at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22476
