--- /dev/null
+dnl AC_CHECK_VA_COPY: check for C99 va_copy() implementation (and
+dnl provide fallback implementation if neccessary)
+
+dnl This code is stolen from the OSSP ex autoconf macros by
+dnl Ralf S. Engelschall.
+dnl # ``"Reuse an expert's code" is the right
+dnl # advice for most people. But it's a useless
+dnl # advice for the experts writing the code
+dnl # in the first place.'
+dnl # -- Dan J. Bernstein
+dnl
+dnl OK, you're definitely the expert on this point... :)
+
+dnl ##
+dnl ## Check for C99 va_copy() implementation
+dnl ## (and provide fallback implementation if neccessary)
+dnl ##
+dnl ## configure.in:
+dnl ## AC_CHECK_VA_COPY
+dnl ## foo.c:
+dnl ## #include "config.h"
+dnl ## [...]
+dnl ## va_copy(d,s)
+dnl ##
+dnl ## This check is rather complex: first because we really have to
+dnl ## try various possible implementations in sequence and second, we
+dnl ## cannot define a macro in config.h with parameters directly.
+dnl ##
+
+dnl # test program for va_copy() implementation
+changequote(<<,>>)
+m4_define(__va_copy_test, <<[
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#define DO_VA_COPY(d, s) $1
+void test(char *str, ...)
+{
+ va_list ap, ap2;
+ int i;
+ va_start(ap, str);
+ DO_VA_COPY(ap2, ap);
+ for (i = 1; i <= 9; i++) {
+ int k = (int)va_arg(ap, int);
+ if (k != i)
+ abort();
+ }
+ DO_VA_COPY(ap, ap2);
+ for (i = 1; i <= 9; i++) {
+ int k = (int)va_arg(ap, int);
+ if (k != i)
+ abort();
+ }
+ va_end(ap);
+}
+int main(int argc, char *argv[])
+{
+ test("test", 1, 2, 3, 4, 5, 6, 7, 8, 9);
+ exit(0);
+}
+]>>)
+changequote([,])
+
+dnl # test driver for va_copy() implementation
+m4_define(__va_copy_check, [
+ AH_VERBATIM($1,
+[/* Predefined possible va_copy() implementation (id: $1) */
+#define __VA_COPY_USE_$1(d, s) $2])
+ if test ".$ac_cv_va_copy" = .; then
+ AC_TRY_RUN(__va_copy_test($2), [ac_cv_va_copy="$1"])
+ fi
+])
+
+dnl # Autoconf check for va_copy() implementation checking
+AC_DEFUN([AC_CHECK_VA_COPY],[
+ dnl # provide Autoconf display check message
+ AC_MSG_CHECKING(for va_copy() function)
+ dnl # check for various implementations in priorized sequence
+ AC_CACHE_VAL(ac_cv_va_copy, [
+ ac_cv_va_copy=""
+ dnl # 1. check for standardized C99 macro
+ __va_copy_check(C99, [va_copy((d), (s))])
+ dnl # 2. check for alternative/deprecated GCC macro
+ __va_copy_check(GCM, [VA_COPY((d), (s))])
+ dnl # 3. check for internal GCC macro (high-level define)
+ __va_copy_check(GCH, [__va_copy((d), (s))])
+ dnl # 4. check for internal GCC macro (built-in function)
+ __va_copy_check(GCB, [__builtin_va_copy((d), (s))])
+ dnl # 5. check for assignment approach (assuming va_list is a struct)
+ __va_copy_check(ASS, [do { (d) = (s); } while (0)])
+ dnl # 6. check for assignment approach (assuming va_list is a pointer)
+ __va_copy_check(ASP, [do { *(d) = *(s); } while (0)])
+ dnl # 7. check for memory copying approach (assuming va_list is a struct)
+ __va_copy_check(CPS, [memcpy((void *)&(d), (void *)&(s)), sizeof((s))])
+ dnl # 8. check for memory copying approach (assuming va_list is a pointer)
+ __va_copy_check(CPP, [memcpy((void *)(d), (void *)(s)), sizeof(*(s))])
+ if test ".$ac_cv_va_copy" = .; then
+ AC_ERROR([no working implementation found])
+ fi
+ ])
+ dnl # optionally activate the fallback implementation
+ if test ".$ac_cv_va_copy" = ".C99"; then
+ AC_DEFINE(HAVE_VA_COPY, 1, [Define if va_copy() macro exists (and no fallback implementation is required)])
+ fi
+ dnl # declare which fallback implementation to actually use
+ AC_DEFINE_UNQUOTED([__VA_COPY_USE], [__VA_COPY_USE_$ac_cv_va_copy],
+ [Define to id of used va_copy() implementation])
+ dnl # provide activation hook for fallback implementation
+ AH_VERBATIM([__VA_COPY_ACTIVATION],
+[/* Optional va_copy() implementation activation */
+#ifndef HAVE_VA_COPY
+#define va_copy(d, s) __VA_COPY_USE(d, s)
+#endif
+])
+ dnl # provide Autoconf display result message
+ if test ".$ac_cv_va_copy" = ".C99"; then
+ AC_MSG_RESULT([yes])
+ else
+ AC_MSG_RESULT([no (using fallback implementation)])
+ fi
+])
+
