Experimental Physics and
Industrial Control System

Martin Konrad via Core-talk <[email protected]> · Tue, 07 Jan 2020 14:53:05 -0000

Mark, you're right, MSVC supports %z for size_t (which is certainly
preferred over the Microsoft-specific %I). This is supported at least
since VS 2015 (https://docs.microsoft.com/en-us/cpp/c-runtime-library
/format-specification-syntax-printf-and-wprintf-functions?view=vs-2015
#size-prefixes-for-printf-and-wprintf-format-type-specifiers). But I'm
not aware of a sane portable way of writing

int64_t i = 42;
printf("Works on Windows only: %I64d\n", i);

other than

printf("Works on all C99-compatible platforms: %"PRId64"\n", i);

Sure the following works

printf("Works on all C99-compatible platforms: %lli\n", (long long)i);

but I always have to pull up the standard to be sure the type I'm
casting to has sufficient size on all platforms. And it also requires
C99.

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https://bugs.launchpad.net/bugs/1740426

Title:
  portable printf() spec for size_t, long long, and others

Status in EPICS Base:
  Triaged

Bug description:
  I've been in the habit of using '%lld' and '%zu' to print 'long long'
  and 'size_t' respectively.  However, the windows world needs '%I64d'
  and '%Iu' instead.  It would be nice to have compatibility macros for
  this.

  stdint.h/inttypes.h has a convention for this for the standard fixed
  width types.  eg. PRIx32 for 'uint32_t'.  This is used like:

  > printf("%"PRIx32"\n", (uint32_t)42);

  http://en.cppreference.com/w/c/types/integer

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System