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112 lines
3.7 KiB
Plaintext
112 lines
3.7 KiB
Plaintext
# va_copy.m4 serial 1 (js-1.6.20070208)
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dnl ##
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dnl ## Check for C99 va_copy() implementation
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dnl ## (and provide fallback implementation if neccessary)
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dnl ##
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dnl ## configure.in:
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dnl ## AC_CHECK_VA_COPY
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dnl ## foo.c:
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dnl ## #include "config.h"
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dnl ## [...]
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dnl ## va_copy(d,s)
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dnl ##
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dnl ## This check is rather complex: first because we really have to
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dnl ## try various possible implementations in sequence and second, we
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dnl ## cannot define a macro in config.h with parameters directly.
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dnl ##
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dnl # test program for va_copy() implementation
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changequote(<<,>>)
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m4_define(__va_copy_test, <<[
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#include <stdlib.h>
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#include <stdarg.h>
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#include <string.h>
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#define DO_VA_COPY(d, s) $1
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void test(char *str, ...)
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{
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va_list ap, ap2;
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int i;
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va_start(ap, str);
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DO_VA_COPY(ap2, ap);
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for (i = 1; i <= 9; i++) {
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int k = (int)va_arg(ap, int);
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if (k != i)
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abort();
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}
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DO_VA_COPY(ap, ap2);
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for (i = 1; i <= 9; i++) {
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int k = (int)va_arg(ap, int);
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if (k != i)
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abort();
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}
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va_end(ap);
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}
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int main(int argc, char *argv[])
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{
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test("test", 1, 2, 3, 4, 5, 6, 7, 8, 9);
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exit(0);
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}
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]>>)
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changequote([,])
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dnl # test driver for va_copy() implementation
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m4_define(__va_copy_check, [
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AH_VERBATIM($1,
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[/* Predefined possible va_copy() implementation (id: $1) */
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#define __VA_COPY_USE_$1(d, s) $2])
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if test ".$ac_cv_va_copy" = .; then
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AC_TRY_RUN(__va_copy_test($2), [ac_cv_va_copy="$1"])
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fi
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])
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dnl # Autoconf check for va_copy() implementation checking
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AC_DEFUN([AC_CHECK_VA_COPY],[
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dnl # provide Autoconf display check message
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AC_MSG_CHECKING(for va_copy() function)
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dnl # check for various implementations in priorized sequence
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AC_CACHE_VAL(ac_cv_va_copy, [
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ac_cv_va_copy=""
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dnl # 1. check for standardized C99 macro
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__va_copy_check(C99, [va_copy((d), (s))])
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dnl # 2. check for alternative/deprecated GCC macro
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__va_copy_check(GCM, [VA_COPY((d), (s))])
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dnl # 3. check for internal GCC macro (high-level define)
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__va_copy_check(GCH, [__va_copy((d), (s))])
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dnl # 4. check for internal GCC macro (built-in function)
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__va_copy_check(GCB, [__builtin_va_copy((d), (s))])
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dnl # 5. check for assignment approach (assuming va_list is a struct)
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__va_copy_check(ASS, [do { (d) = (s); } while (0)])
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dnl # 6. check for assignment approach (assuming va_list is a pointer)
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__va_copy_check(ASP, [do { *(d) = *(s); } while (0)])
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dnl # 7. check for memory copying approach (assuming va_list is a struct)
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__va_copy_check(CPS, [memcpy((void *)&(d), (void *)&(s)), sizeof((s))])
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dnl # 8. check for memory copying approach (assuming va_list is a pointer)
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__va_copy_check(CPP, [memcpy((void *)(d), (void *)(s)), sizeof(*(s))])
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if test ".$ac_cv_va_copy" = .; then
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AC_ERROR([no working implementation found])
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fi
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])
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dnl # optionally activate the fallback implementation
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if test ".$ac_cv_va_copy" = ".C99"; then
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AC_DEFINE(HAVE_VA_COPY, 1, [Define if va_copy() macro exists (and no fallback implementation is required)])
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fi
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dnl # declare which fallback implementation to actually use
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AC_DEFINE_UNQUOTED([__VA_COPY_USE], [__VA_COPY_USE_$ac_cv_va_copy],
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[Define to id of used va_copy() implementation])
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dnl # provide activation hook for fallback implementation
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AH_VERBATIM([__VA_COPY_ACTIVATION],
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[/* Optional va_copy() implementation activation */
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#ifndef HAVE_VA_COPY
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#define va_copy(d, s) __VA_COPY_USE(d, s)
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#endif
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])
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dnl # provide Autoconf display result message
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if test ".$ac_cv_va_copy" = ".C99"; then
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AC_MSG_RESULT([yes])
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else
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AC_MSG_RESULT([no (using fallback implementation)])
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fi
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])
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