lib/, src/, tests/: Use the standard countof() instead of our NITEMS()

[alejandro-colomar]

countof() is the name blessed by the C Committee for this macro in ISO C2y. Use it if available, and define it if not.

countof() will be provided by GCC 16 and Clang 21.

This is mostly a scripted change:

$ grep -rl NITEMS | xargs sed -i s/NITEMS/countof/;

Link: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3550.pdf#subsubsection.0.6.5.4.5
Link: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3550.pdf#section.0.7.21

---

Revisions:

v1b

• Rebase

$ git rd 
1:  4713ce66 ! 1:  40627ab6 lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
    @@ lib/string/strcpy/strtcpy.h
     
      ## lib/string/strdup/strndupa.h ##
     @@
    - // Similar to strndupa(3), but ensure that 's' is an array.
    - #define STRNDUPA(s)                                                           \
    - (                                                                             \
    --  STRNCAT(strcpy(alloca(strnlen(s, NITEMS(s)) + 1), ""), s)             \
    -+  STRNCAT(strcpy(alloca(strnlen(s, countof(s)) + 1), ""), s)            \
    - )
    + #endif
      
      
    +-#define STRNDUPA(s)  strndupa(s, NITEMS(s))
    ++#define STRNDUPA(s)  strndupa(s, countof(s))
    + 
    + 
    + #endif  // include guard
     
      ## lib/string/strdup/xstrndup.h ##
     @@
2:  52ee105d = 2:  0272ba8a lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  ee4de260 = 3:  e30e207b autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  2efe549e = 4:  e12ab0f3 lib/, src/: Move macros to "typetraits.h"

v2

• Use countof() instead of its pattern.

$ git rd
1:  40627ab6 = 1:  40627ab6 lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
2:  0272ba8a = 2:  0272ba8a lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  e30e207b = 3:  e30e207b autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  e12ab0f3 = 4:  e12ab0f3 lib/, src/: Move macros to "typetraits.h"
-:  -------- > 5:  48e5e851 lib/getdef.c: Use countof() instead of its pattern

v2b

• Rebase

$ git rd
1:  40627ab6 = 1:  b137a0c2 lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
2:  0272ba8a = 2:  6d8e0251 lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  e30e207b = 3:  25dd20d8 autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  e12ab0f3 = 4:  fc614d10 lib/, src/: Move macros to "typetraits.h"
5:  48e5e851 = 5:  33ff0383 lib/getdef.c: Use countof() instead of its pattern

v2c

• Rebase

$ git rd
1:  b137a0c2 = 1:  b59ac227 lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
2:  6d8e0251 = 2:  fa754b3c lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  25dd20d8 = 3:  bc6210cc autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  fc614d10 = 4:  444c3623 lib/, src/: Move macros to "typetraits.h"
5:  33ff0383 = 5:  658841f7 lib/getdef.c: Use countof() instead of its pattern

v2d

• Rebase

$ git rd
1:  b59ac227 = 1:  45299b55 lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
2:  fa754b3c = 2:  17c3d556 lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  bc6210cc = 3:  56fa3975 autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  444c3623 = 4:  db2946cc lib/, src/: Move macros to "typetraits.h"
5:  658841f7 = 5:  35c87a1f lib/getdef.c: Use countof() instead of its pattern

v2e

• Rebase

$ git rd
1:  45299b55 = 1:  37e5c4fe lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
2:  17c3d556 = 2:  eef531a4 lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  56fa3975 = 3:  ceb70a65 autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  db2946cc = 4:  93dbe0a5 lib/, src/: Move macros to "typetraits.h"
5:  35c87a1f = 5:  bf02a07f lib/getdef.c: Use countof() instead of its pattern

v2f

• Rebase

$ git rd
1:  37e5c4fe = 1:  5612b0a4 lib/, src/, tests/: Use the standard countof() instead of our NITEMS()
2:  eef531a4 = 2:  20299e3e lib/sizeof.h: Define SIZEOF_ARRAY() in terms of countof()
3:  ceb70a65 = 3:  842ae501 autogen.sh, lib/: Replace must_be_array() by -Werror=sizeof-pointer-div
4:  93dbe0a5 = 4:  633661de lib/, src/: Move macros to "typetraits.h"
5:  bf02a07f = 5:  8cbd0e76 lib/getdef.c: Use countof() instead of its pattern

[alejandro-colomar]

Note: GCC hasn't yet merged the patches implementing _Countof and <stdcountof.h>, but it's a matter of days or weeks. Clang has already merged that.

[alejandro-colomar]

Note: GCC hasn't yet merged the patches implementing _Countof and <stdcountof.h>, but it's a matter of days or weeks. Clang has already merged that.

Aaaaand, done! GCC has merged my patches implementing _Countof and <stdcountof.h> today: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117025#c3. :-)