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Windows: Disable MinGW-w64's stdio functions in size-optimized builds 

This only affects builds with UCRT. With legacy MSVCRT, the replacement
functions are always enabled.

Omitting the MinGW-w64 replacements saves over 20 KiB per executable.
The downside is that --enable-small or XZ_SMALL=ON disables thousand
separator support in xz messages. If someone is OK with the slower
speed of slightly smaller builds, lack of thousand separators won't
matter.

Don't override __USE_MINGW_ANSI_STDIO if it is already defined (via
CPPFLAGS or such method).
This commit is contained in:
Lasse Collin 2025-01-22 15:03:55 +02:00
parent a831bc185b
commit 4eae859ae8
No known key found for this signature in database
GPG Key ID: 38EE757D69184620
2 changed files with 26 additions and 10 deletions
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30
src/common/sysdefs.h
View File

@ -23,17 +23,29 @@
# include <config.h>
#endif
// This #define ensures that C99 and POSIX compliant stdio functions are
// available with MinGW-w64 (both 32-bit and 64-bit). Modern MinGW-w64 adds
// this automatically, for example, when the compiler is in C99 (or later)
// mode when building against msvcrt.dll. It still doesn't hurt to be explicit
// that we always want this and #define this unconditionally.
// Choose if MinGW-w64's stdio replacement functions should be used.
// The default has varied slightly in the past so it's clearest to always
// set it explicitly.
//
// With Universal CRT (UCRT) this is less important because UCRT contains
// C99-compatible stdio functions. It's still nice to #define this as UCRT
// doesn't support the POSIX thousand separator flag in printf (like "%'u").
#ifdef __MINGW32__
// Modern MinGW-w64 enables the replacement functions even with UCRT
// when _GNU_SOURCE is defined. That's good because UCRT doesn't support
// the POSIX thousand separator flag in printf (like "%'u"). Otherwise
// XZ Utils works with the UCRT stdio functions.
//
// The replacement functions add over 20 KiB to each executable. For
// size-optimized builds (HAVE_SMALL), disable the replacements.
// Then thousand separators aren't shown in xz's messages but this is
// a minor downside compare to the slower speed of the HAVE_SMALL builds.
//
// The legacy MSVCRT is pre-C99 and it's best to always use the stdio
// replacements functions from MinGW-w64.
#if defined(__MINGW32__) && !defined(__USE_MINGW_ANSI_STDIO)
# define __USE_MINGW_ANSI_STDIO 1
# include <_mingw.h>
# if defined(_UCRT) && defined(HAVE_SMALL)
# undef __USE_MINGW_ANSI_STDIO
# define __USE_MINGW_ANSI_STDIO 0
# endif
#endif
// size_t and NULL

6
src/xz/util.c
View File

@ -25,7 +25,11 @@ static char bufs[4][128];
// for DJGPP builds.
//
// MSVC doesn't support thousand separators.
#if defined(__DJGPP__) || defined(_MSC_VER)
//
// MinGW-w64 supports thousand separators only with its own stdio functions
// which our sysdefs.h disables when _UCRT && HAVE_SMALL.
#if defined(__DJGPP__) || defined(_MSC_VER) \
|| (defined(__MINGW32__) && __USE_MINGW_ANSI_STDIO == 0)
# define FORMAT_THOUSAND_SEP(prefix, suffix) prefix suffix
# define check_thousand_sep(slot) do { } while (0)
#else