Mail Archives: cygwin/1997/10/06/19:36:55
In article <34391696 DOT 27758E19 AT softway DOT com>,
Jason Zions <jazz AT softway DOT com> wrote:
>> I have found that the following bad code gives "exception" at run
>> time instead of error message at compilation time (b18 Win95):
>>
>> #include <stdio.h>
>> main(){
>> printf("%s\n",sizeof(long));
>> }
>
>No compiler will detect this error at compile-time. The prototype for
>printf is (char *, ...); that is, no specific type information for
>anything except the first parameter. A compiler would have to read the
>first parameter to figure out the expected types for the remaining
>args, and much of the time that first parameter is dynamically computed
>at runtime instead of being a static string. There are a couple of
>lint-like programs that will catch this error with a
>compile-time-evaluatable format string, but that's the best you can do.
>
>Summary: learn more about the language before whining about compiler
>errors. This is a programmer bug, not a compiler bug.
Actually, this is a little harsh since GCC does, in fact, have a compile
time __attribute__ option for checking the arguments to a printf. If
the prototype for printf in /usr/include/stdio.h had included something like:
__attribute__((format(printf, 1, 2)));
it would have detected that programmer error.
--
http://www.bbc.com/ cgf AT bbc DOT com "Strange how unreal
VMS=>UNIX Solutions Boston Business Computing the real can be."
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