I have searched about this warning and everyone had some mistake in their code, but here is something very unexpected I could not figure out . We do expect strlen(x) to be an integer but what does this warning tell me? How couldn't strlen be int?
In function ‘fn_product’:
line85:3:warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘size_t’ [-Wformat]
My code in fn_product --
char *fn_product (char x[],char y[]){
if (strlen(x)==1) // line85
printf("\nlength of string--%d\n", strlen(x));
/*other code*/
}
Shouldn't strlen(x) be int.Why does it say to be of format size_t?
Did you check the man page? strlen(3)
returns size_t
. Use %zu
to print it.
As mentioned in the comments below, clang is sometimes helpful with finding better error messages. clang's warning for exactly this case is pretty great, in fact:
example.c:6:14: warning: format specifies type 'unsigned int' but the argument
has type 'size_t' (aka 'unsigned long') [-Wformat]
printf("%u\n", strlen("abcde"));
~^ ~~~~~~~~~~~~~~~
%zu
1 warning generated.