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| -rw-r--r-- | m4/const.m4 | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/m4/const.m4 b/m4/const.m4 new file mode 100644 index 000000000..ebe59596c --- /dev/null +++ b/m4/const.m4 @@ -0,0 +1,66 @@ +#serial 1 + +dnl Just like AC_C_CONST from autoconf-2.12, but with an initializer +dnl for `charset x' and with +dnl AC_DEFINE(const, ) +dnl changed to +dnl AC_DEFINE_UNQUOTED(const, [/* empty */]) +dnl to avoid this warning: +dnl [...]/m4: Warning: Excess arguments to built-in `define' ignored + +undefine([AC_C_CONST]) +AC_DEFUN(AC_C_CONST, +[dnl This message is consistent in form with the other checking messages, +dnl and with the result message. +AC_CACHE_CHECK([for working const], ac_cv_c_const, +[AC_TRY_COMPILE(, +changequote(<<, >>)dnl +<< +/* Ultrix mips cc rejects this. */ +typedef int charset[2]; const charset x = {0, 0}; +/* SunOS 4.1.1 cc rejects this. */ +char const *const *ccp; +char **p; +/* NEC SVR4.0.2 mips cc rejects this. */ +struct point {int x, y;}; +static struct point const zero = {0,0}; +/* AIX XL C 1.02.0.0 rejects this. + It does not let you subtract one const X* pointer from another in an arm + of an if-expression whose if-part is not a constant expression */ +const char *g = "string"; +ccp = &g + (g ? g-g : 0); +/* HPUX 7.0 cc rejects these. */ +++ccp; +p = (char**) ccp; +ccp = (char const *const *) p; +{ /* SCO 3.2v4 cc rejects this. */ + char *t; + char const *s = 0 ? (char *) 0 : (char const *) 0; + + *t++ = 0; +} +{ /* Someone thinks the Sun supposedly-ANSI compiler will reject this. */ + int x[] = {25, 17}; + const int *foo = &x[0]; + ++foo; +} +{ /* Sun SC1.0 ANSI compiler rejects this -- but not the above. */ + typedef const int *iptr; + iptr p = 0; + ++p; +} +{ /* AIX XL C 1.02.0.0 rejects this saying + "k.c", line 2.27: 1506-025 (S) Operand must be a modifiable lvalue. */ + struct s { int j; const int *ap[3]; }; + struct s *b; b->j = 5; +} +{ /* ULTRIX-32 V3.1 (Rev 9) vcc rejects this */ + const int foo = 10; +} +>>, +changequote([, ])dnl +ac_cv_c_const=yes, ac_cv_c_const=no)]) +if test $ac_cv_c_const = no; then + AC_DEFINE_UNQUOTED(const, [/* empty */]) +fi +]) |