1  /* ABI compatibility for lgamma functions.
       2     Copyright (C) 2015-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef LGAMMA_COMPAT_H
      20  #define LGAMMA_COMPAT_H 1
      21  
      22  #include <math-svid-compat.h>
      23  #include <shlib-compat.h>
      24  
      25  /* XSI POSIX requires lgamma to set signgam, but ISO C does not permit
      26     this.  Namespace issues can be avoided if the functions set
      27     __signgam and signgam is a weak alias, but this only works if both
      28     signgam and __signgam were exported from the glibc version the
      29     program was linked against.  Before glibc 2.23, lgamma functions
      30     set signgam which was not a weak alias for __signgam, so old
      31     binaries have dynamic symbols for signgam only and the versions of
      32     lgamma used for old binaries must set both signgam and __signgam.
      33     Those versions also do a check of _LIB_VERSION != _ISOC_ to match
      34     old glibc.
      35  
      36     Users of this file define USE_AS_COMPAT to 0 when building the main
      37     version of lgamma, 1 when building the compatibility version.  */
      38  
      39  #define LGAMMA_OLD_VER GLIBC_2_0
      40  #define LGAMMA_NEW_VER GLIBC_2_23
      41  #define HAVE_LGAMMA_COMPAT SHLIB_COMPAT (libm, LGAMMA_OLD_VER, LGAMMA_NEW_VER)
      42  
      43  /* Whether to build this version at all.  */
      44  #define BUILD_LGAMMA \
      45    (LIBM_SVID_COMPAT && (HAVE_LGAMMA_COMPAT || !USE_AS_COMPAT))
      46  
      47  /* The name to use for this version.  */
      48  #if USE_AS_COMPAT
      49  # define LGFUNC(FUNC) FUNC ## _compat
      50  #else
      51  # define LGFUNC(FUNC) FUNC
      52  #endif
      53  
      54  /* If there is a compatibility version, gamma (not an ISO C function,
      55     so never a problem for it to set signgam) points directly to it
      56     rather than having separate versions.  */
      57  #define GAMMA_ALIAS (USE_AS_COMPAT ? HAVE_LGAMMA_COMPAT : !HAVE_LGAMMA_COMPAT)
      58  
      59  /* How to call the underlying lgamma_r function.  */
      60  #define CALL_LGAMMA(TYPE, FUNC, ARG)			\
      61    ({							\
      62      TYPE lgamma_tmp;					\
      63      int local_signgam;					\
      64      if (USE_AS_COMPAT)					\
      65        {							\
      66  	lgamma_tmp = FUNC ((ARG), &local_signgam);	\
      67  	if (_LIB_VERSION != _ISOC_)			\
      68  	  signgam = __signgam = local_signgam;		\
      69        }							\
      70      else						\
      71        lgamma_tmp = FUNC ((ARG), &__signgam);		\
      72      lgamma_tmp;						\
      73    })
      74  
      75  #endif /* lgamma-compat.h.  */