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| author | Florian Weimer <fweimer@redhat.com> | 2019-02-07 09:03:02 +0100 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2019-02-07 09:03:02 +0100 |
| commit | 8311c83f91a3127ccd2fe684e25bc60c5178d23b (patch) | |
| tree | 795aaabcfdd4b0be64899c653ea74e930be34c3e | |
| parent | 94b63e66206a9ad38872a9136a623ce73cf7c858 (diff) | |
| download | glibc-8311c83f91a3127ccd2fe684e25bc60c5178d23b.tar.gz glibc-8311c83f91a3127ccd2fe684e25bc60c5178d23b.tar.xz glibc-8311c83f91a3127ccd2fe684e25bc60c5178d23b.zip | |
array_length: Make usable as a constant expression
Do not use a statement expression in array_length, so that array_length can be used at file scope and as a constant expression. Instead, put the _Static_assert into a struct (as a declaration), and nest this in the expression using a sizeof expression.
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | include/array_length.h | 12 |
2 files changed, 12 insertions, 6 deletions
diff --git a/ChangeLog b/ChangeLog index 1c477228f3..3270662983 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ 2019-02-07 Florian Weimer <fweimer@redhat.com> + * include/array_length.h (array_length): Do not use a statement + expression and _Static_assert, so that array_length can be used at + file scope and as a constant expression. + +2019-02-07 Florian Weimer <fweimer@redhat.com> + * support/xdlfcn.h (xdlmopen): Declare. * support/xdlmopen.c: New file. * support/Makefile (libsupport-routines): Add xdlmopen. diff --git a/include/array_length.h b/include/array_length.h index 65f583063d..db98a69899 100644 --- a/include/array_length.h +++ b/include/array_length.h @@ -22,12 +22,12 @@ /* array_length (VAR) is the number of elements in the array VAR. VAR must evaluate to an array, not a pointer. */ #define array_length(var) \ - __extension__ ({ \ - _Static_assert (!__builtin_types_compatible_p \ - (__typeof (var), __typeof (&(var)[0])), \ - "argument must be an array"); \ - sizeof (var) / sizeof ((var)[0]); \ - }) + (sizeof (var) / sizeof ((var)[0]) \ + + 0 * sizeof (struct { \ + _Static_assert (!__builtin_types_compatible_p \ + (__typeof (var), __typeof (&(var)[0])), \ + "argument must be an array"); \ + })) /* array_end (VAR) is a pointer one past the end of the array VAR. VAR must evaluate to an array, not a pointer. */ |