printf format specifiers for Perl API types

Question

Are there macros that provide the correct printf format specifiers for IV, UV, STRLEN, Size_t and SSize_t? None are listed in perlapi.

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C provides macros for the format specifiers for the types provided by stdint.h, such as uint32_t.

#include <inttypes.h>
#include <stdint.h>

uint32_t i = ...;
printf("i = %" PRIu32 "\n", i);

Is there something similar to PRIu32 for IV, UV, STRLEN, Size_t and SSize_t?

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The larger problem is that I'm trying to suggest a fix for the following compilation warnings produced when installing Sort::Key on Ubuntu on Windows Subsystem for Linux:

Key.xs: In function ‘_keysort’:
Key.xs:237:12: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘IV {aka long int}’ [-Wformat=]
      croak("unsupported sort type %d", type);
            ^~~~~~~~~~~~~~~~~~~~~~~~~~
Key.xs: In function ‘_multikeysort’:
Key.xs:547:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘STRLEN {aka long unsigned int}’ [-Wformat=]
   croak("wrong number of results returned "
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Key.xs:547:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘IV {aka long int}’ [-Wformat=]

Answer 1

• For UV, the following macros exist:

  • UVuf (decimal)
  • UVof (octal)
  • UVxf (lc hex)
  • UVXf (uc hex)

• For IV, the following macro exists:

  • IVdf (decimal)

• For NV, the following macros exist:

  • NVef ("%e-ish")
  • NVff ("%f-ish")
  • NVgf ("%g-ish")

• For Size_t and STRLEN, use the builtin z length modifier.^[1]

  • %zu (decimal)
  • %zo (octal)
  • %zx (lc hex)
  • %zX (uc hex)

• For SSize_t, use the builtin z length modifier.^[1]

  • %zd (decimal)

For example,

IV iv      = ...;
STRLEN len = ...;

croak("iv=%" IVdf " len=%zu", iv, len);

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1. While Size_t and SSize_t are configurable, they're never different from size_t and ssize_t in practice, and STRLEN is a typedef for Size_t.