How can one print a size_t variable portably using the printf family?

Question

I have a variable of type size_t, and I want to print it using printf(). What format specifier do I use to print it portably?

In 32-bit ma

Answer 1

Extending on Adam Rosenfield's answer for Windows.

I tested this code with on both VS2013 Update 4 and VS2015 preview:

// test.c

#include 
#include  // see the note below

int main()
{
    size_t x = 1;
    SSIZE_T y = 2;
    printf("%zu\n", x);  // prints as unsigned decimal
    printf("%zx\n", x);  // prints as hex
    printf("%zd\n", y);  // prints as signed decimal
    return 0;
}

VS2015 generated binary outputs:

1
1
2

while the one generated by VS2013 says:

zu
zx
zd

Note: ssize_t is a POSIX extension and SSIZE_T is similar thing in Windows Data Types, hence I added reference.

Additionally, except for the follow C99/C11 headers, all C99 headers are available in VS2015 preview:

C11 - 
C11 - 
C11 - 
C99 - 
C11 - 

Also, C11's is now included in latest preview.

For more details, see this old and the new list for standard conformance.