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Diffstat (limited to '')
| -rw-r--r-- | m4/warn-on-use.m4 | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/m4/warn-on-use.m4 b/m4/warn-on-use.m4 new file mode 100644 index 0000000..10649c5 --- /dev/null +++ b/m4/warn-on-use.m4 @@ -0,0 +1,62 @@ +# warn-on-use.m4 serial 10 +dnl Copyright (C) 2010-2023 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +# gl_WARN_ON_USE_PREPARE(INCLUDES, NAMES) +# --------------------------------------- +# If the module 'posixcheck' is in use: +# +# For each whitespace-separated element in the list of NAMES, define +# HAVE_RAW_DECL_name if the function has a declaration among INCLUDES +# even after being undefined as a macro. +# +# See warn-on-use.h for some hints on how to poison function names, as +# well as ideas on poisoning global variables and macros. NAMES may +# include global variables, but remember that only functions work with +# _GL_WARN_ON_USE. Typically, INCLUDES only needs to list a single +# header, but if the replacement header pulls in other headers because +# some systems declare functions in the wrong header, then INCLUDES +# should do likewise. +# +# It is generally safe to assume declarations for functions declared +# in the intersection of C89 and C11 (such as printf) without +# needing gl_WARN_ON_USE_PREPARE. +AC_DEFUN([gl_WARN_ON_USE_PREPARE], +[ + m4_ifdef([gl_POSIXCHECK], + [m4_foreach_w([gl_decl], [$2], + [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])), + [Define to 1 if ]m4_defn([gl_decl])[ is declared even after + undefining macros.])])dnl + for gl_func in m4_flatten([$2]); do + AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl + dnl As a workaround to implicit built-in function declarations in + dnl clang (e.g. strndup), reference ac_compile_for_check_decl instead + dnl of ac_compile. If, for whatever reason, the override of AC_PROG_CC + dnl in zzgnulib.m4 is inactive, use the original ac_compile. + ac_save_ac_compile="$ac_compile" + if test -n "$ac_compile_for_check_decl"; then + ac_compile="$ac_compile_for_check_decl" + fi + AC_CACHE_CHECK([whether $gl_func is declared without a macro], + [gl_Symbol], + [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1], +[[#undef $gl_func + (void) $gl_func;]])], + [AS_VAR_SET([gl_Symbol], [yes])], [AS_VAR_SET([gl_Symbol], [no])])]) + ac_compile="$ac_save_ac_compile" + AS_VAR_IF([gl_Symbol], [yes], + [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1]) + dnl Shortcut for an AC_CHECK_DECL invocation that may come later: + dnl If the raw declaration exists with the given includes, then + dnl AC_CHECK_DECL with its many includes would see it as well. + dnl So, set a cache variable to allow skipping any later + dnl AC_CHECK_DECL invocation for $gl_func. + eval "ac_cv_have_decl_$gl_func=yes" + ]) + AS_VAR_POPDEF([gl_Symbol])dnl + done + ]) +]) |