| 1 | # va_copy.m4 serial 1 (js-1.6.20070208) |
| 2 | |
| 3 | dnl ## |
| 4 | dnl ## Check for C99 va_copy() implementation |
| 5 | dnl ## (and provide fallback implementation if neccessary) |
| 6 | dnl ## |
| 7 | dnl ## configure.in: |
| 8 | dnl ## AC_CHECK_VA_COPY |
| 9 | dnl ## foo.c: |
| 10 | dnl ## #include "config.h" |
| 11 | dnl ## [...] |
| 12 | dnl ## va_copy(d,s) |
| 13 | dnl ## |
| 14 | dnl ## This check is rather complex: first because we really have to |
| 15 | dnl ## try various possible implementations in sequence and second, we |
| 16 | dnl ## cannot define a macro in config.h with parameters directly. |
| 17 | dnl ## |
| 18 | |
| 19 | dnl # test program for va_copy() implementation |
| 20 | changequote(<<,>>) |
| 21 | m4_define(__va_copy_test, <<[ |
| 22 | #include <stdlib.h> |
| 23 | #include <stdarg.h> |
| 24 | #include <string.h> |
| 25 | #define DO_VA_COPY(d, s) $1 |
| 26 | void test(char *str, ...) |
| 27 | { |
| 28 | va_list ap, ap2; |
| 29 | int i; |
| 30 | va_start(ap, str); |
| 31 | DO_VA_COPY(ap2, ap); |
| 32 | for (i = 1; i <= 9; i++) { |
| 33 | int k = (int)va_arg(ap, int); |
| 34 | if (k != i) |
| 35 | abort(); |
| 36 | } |
| 37 | DO_VA_COPY(ap, ap2); |
| 38 | for (i = 1; i <= 9; i++) { |
| 39 | int k = (int)va_arg(ap, int); |
| 40 | if (k != i) |
| 41 | abort(); |
| 42 | } |
| 43 | va_end(ap); |
| 44 | } |
| 45 | int main(int argc, char *argv[]) |
| 46 | { |
| 47 | test("test", 1, 2, 3, 4, 5, 6, 7, 8, 9); |
| 48 | exit(0); |
| 49 | } |
| 50 | ]>>) |
| 51 | changequote([,]) |
| 52 | |
| 53 | dnl # test driver for va_copy() implementation |
| 54 | m4_define(__va_copy_check, [ |
| 55 | AH_VERBATIM($1, |
| 56 | [/* Predefined possible va_copy() implementation (id: $1) */ |
| 57 | #define __VA_COPY_USE_$1(d, s) $2]) |
| 58 | if test ".$ac_cv_va_copy" = .; then |
| 59 | AC_TRY_RUN(__va_copy_test($2), [ac_cv_va_copy="$1"]) |
| 60 | fi |
| 61 | ]) |
| 62 | |
| 63 | dnl # Autoconf check for va_copy() implementation checking |
| 64 | AC_DEFUN([AC_CHECK_VA_COPY],[ |
| 65 | dnl # provide Autoconf display check message |
| 66 | AC_MSG_CHECKING(for va_copy() function) |
| 67 | dnl # check for various implementations in priorized sequence |
| 68 | AC_CACHE_VAL(ac_cv_va_copy, [ |
| 69 | ac_cv_va_copy="" |
| 70 | dnl # 1. check for standardized C99 macro |
| 71 | __va_copy_check(C99, [va_copy((d), (s))]) |
| 72 | dnl # 2. check for alternative/deprecated GCC macro |
| 73 | __va_copy_check(GCM, [VA_COPY((d), (s))]) |
| 74 | dnl # 3. check for internal GCC macro (high-level define) |
| 75 | __va_copy_check(GCH, [__va_copy((d), (s))]) |
| 76 | dnl # 4. check for internal GCC macro (built-in function) |
| 77 | __va_copy_check(GCB, [__builtin_va_copy((d), (s))]) |
| 78 | dnl # 5. check for assignment approach (assuming va_list is a struct) |
| 79 | __va_copy_check(ASS, [do { (d) = (s); } while (0)]) |
| 80 | dnl # 6. check for assignment approach (assuming va_list is a pointer) |
| 81 | __va_copy_check(ASP, [do { *(d) = *(s); } while (0)]) |
| 82 | dnl # 7. check for memory copying approach (assuming va_list is a struct) |
| 83 | __va_copy_check(CPS, [memcpy((void *)&(d), (void *)&(s)), sizeof((s))]) |
| 84 | dnl # 8. check for memory copying approach (assuming va_list is a pointer) |
| 85 | __va_copy_check(CPP, [memcpy((void *)(d), (void *)(s)), sizeof(*(s))]) |
| 86 | if test ".$ac_cv_va_copy" = .; then |
| 87 | AC_ERROR([no working implementation found]) |
| 88 | fi |
| 89 | ]) |
| 90 | dnl # optionally activate the fallback implementation |
| 91 | if test ".$ac_cv_va_copy" = ".C99"; then |
| 92 | AC_DEFINE(HAVE_VA_COPY, 1, [Define if va_copy() macro exists (and no fallback implementation is required)]) |
| 93 | fi |
| 94 | dnl # declare which fallback implementation to actually use |
| 95 | AC_DEFINE_UNQUOTED([__VA_COPY_USE], [__VA_COPY_USE_$ac_cv_va_copy], |
| 96 | [Define to id of used va_copy() implementation]) |
| 97 | dnl # provide activation hook for fallback implementation |
| 98 | AH_VERBATIM([__VA_COPY_ACTIVATION], |
| 99 | [/* Optional va_copy() implementation activation */ |
| 100 | #ifndef HAVE_VA_COPY |
| 101 | #define va_copy(d, s) __VA_COPY_USE(d, s) |
| 102 | #endif |
| 103 | ]) |
| 104 | dnl # provide Autoconf display result message |
| 105 | if test ".$ac_cv_va_copy" = ".C99"; then |
| 106 | AC_MSG_RESULT([yes]) |
| 107 | else |
| 108 | AC_MSG_RESULT([no (using fallback implementation)]) |
| 109 | fi |
| 110 | ]) |
| 111 | |
| 112 | |
