#3384 closed enhancement (fixed)
Prefer int for int32_t
Reported by: | Sebastian Huber | Owned by: | Sebastian Huber |
---|---|---|---|
Priority: | normal | Milestone: | 5.1 |
Component: | tool/gcc | Version: | 5 |
Severity: | normal | Keywords: | |
Cc: | Blocked By: | ||
Blocking: |
Description
Common systems like Linux and FreeBSD define int32_t to int. This means a lot of third party code works well in these cases:
#include <stdint.h> void f(int32_t); void f(int); void g(int32_t *); void h(void) { int i; g(&i); }
On RTEMS you get however in C
test.c:5:6: error: conflicting types for 'f' void f(int); ^ test.c:3:6: note: previous declaration of 'f' was here void f(int32_t); ^ test.c: In function 'h': test.c:12:4: warning: passing argument 1 of 'g' from incompatible pointer type [-Wincompatible-pointer-types] g(&i); ^ test.c:7:6: note: expected 'int32_t * {aka long int *}' but argument is of type 'int *' void g(int32_t *);
and C++
test.c: In function 'void h()': test.c:12:4: error: invalid conversion from 'int*' to 'int32_t* {aka long int*}' [-fpermissive] g(&i); ^~ test.c:7:6: note: initializing argument 1 of 'void g(int32_t*)' void g(int32_t *); ^
This is due to a Newlib speciality which uses long for int32_t if long is a 32-bit type. To ease the use of third party software in RTEMS we should override this option and use int for int32_t just like the standard host operating systems (e.g. Linux and FreeBSD). Only a small GCC patch is required to do this:
diff --git a/gcc/config/rtems.h b/gcc/config/rtems.h index 439199d4cbb..9b1408efe6f 100644 --- a/gcc/config/rtems.h +++ b/gcc/config/rtems.h @@ -48,3 +48,7 @@ -latomic -lc -lgcc --end-group %{!qnolinkcmds: -T linkcmds%s}}}" #define TARGET_POSIX_IO + +/* Use int for int32_t (see stdint-newlib.h). */ +#undef STDINT_LONG32 +#define STDINT_LONG32 0
Change History (10)
comment:1 Changed on 04/09/18 at 13:39:53 by Joel Sherrill
comment:2 Changed on 04/09/18 at 13:46:46 by Sebastian Huber
See newlib-stdint.h in GCC sources:
[...] #define INT32_TYPE (STDINT_LONG32 ? "long int" : INT_TYPE_SIZE == 32 ? "int" : SHORT_TYPE_SIZE == 32 ? "short int" : CHAR_TYPE_SIZE == 32 ? "signed char" : 0) [...]
So, 16-bit targets should not use this option.
comment:3 Changed on 06/14/18 at 05:21:24 by Sebastian Huber
comment:4 Changed on 06/14/18 at 05:23:35 by Sebastian Huber
Summary: | Change int32_t to int → Prefer int for int32_t |
---|
comment:5 Changed on 12/11/18 at 07:39:39 by Sebastian Huber <sebastian.huber@…>
comment:6 Changed on 12/13/18 at 10:34:46 by Sebastian Huber <sebastian.huber@…>
comment:9 Changed on 12/13/19 at 06:07:14 by Sebastian Huber
Resolution: | → fixed |
---|---|
Status: | assigned → closed |
comment:10 Changed on 12/13/19 at 06:07:28 by Sebastian Huber
Version: | → 5 |
---|
Note: See
TracTickets for help on using
tickets.
Just to keep it clean, what if int is 16 bits on the target?