abi_align.h

/*
	abi_align: ABI and alignment stuff for library builds.

	Original use was the definitions for avoiding breakage because of mixing
	compilers with different alignment. Then, the switchery for building
	DLLs got lumped in.

	copyright 1995-2023 by the mpg123 project
	free software under the terms of the LGPL 2.1
	see COPYING and AUTHORS files in distribution or http://mpg123.org

	There used to be code that checks alignment, but it did not really
	work anyway. The only straw we have is putting that alignment
	attribute to API functions.
*/

#ifndef MPG123_H_ABI_ALIGN
#define MPG123_H_ABI_ALIGN

#include "config.h"

// Building any of our libs on/for Windows needs this before
// including the main API header (define MPG123_EXPORT).
#if defined(WIN32) && defined(DYNAMIC_BUILD)
#define BUILD_MPG123_DLL
#endif

/* ABI conformance for other compilers.
   mpg123 needs 16byte-aligned (or more) stack for SSE and friends.
   gcc provides that, but others don't necessarily. */
#ifdef ABI_ALIGN_FUN

#ifndef attribute_align_arg

#if defined(__GNUC__) && (__GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__>1)
#    define attribute_align_arg __attribute__((force_align_arg_pointer))
/* The gcc that can align the stack does not need the check... nor does it work with gcc 4.3+, anyway. */
#else
#    define attribute_align_arg
#endif

#endif  /* attribute_align_arg */

#else /* ABI_ALIGN_FUN */

#define attribute_align_arg

#endif /* ABI_ALIGN_FUN */

#endif /* MPG123_H_ABI_ALIGN */