Machine-independent printf() of int64_t?

Question

Consider the following snippet, compiled with gcc -Wall for two different architectures:

int64_t x;
printf("A: %ld\n", x);
printf("B: %lld\n", x);

When compiling for a 32 bit machine, the compiler complains about "A":

format '%ld' expects argument of type 'long int', but argument 2 has type 'int64_t' {aka 'long long int'}

When compiling for a 64 bit machine, the compiler complains about "B":

format '%lld' expects argument of type 'long long int', but argument 2 has type 'int64_t' {aka 'long int'}

The question: What is a sensible machine-independent way to printf() int64_t?

Looks like a duplicate of [How to print a int64_t type in C](https://stackoverflow.com/q/9225567/45249). — mouviciel, Oct 18 '22 at 13:51

score 2 · Accepted Answer · answered Oct 18 '22 at 13:49

2

The header inttypes.h contains portable conversion specifiers for printf and scanf family of functions. (It also internally includes stdint.h.)

#include <inttypes.h>

int64_t x = ...;
printf("%"PRIi64, x);

See the C standard C17 7.8.1 for details.

answered Oct 18 '22 at 13:49

Lundin

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Machine-independent printf() of int64_t?

1 Answers1