Importing inttypes.h fails due to misplaced wchar_t definition

[guberti]

Description of the issue:

Including inttypes.h in a .c file fails.

How to reproduce:

The issue should be easy to reproduce by just creating a importer.c file with a single line:

#include <inttypes.h>

Compiling that file will produce the following errors:

In file included from /home/guberti/Desktop/demonstrate_inttypes_bug/importer.c:1:0:
/home/guberti/.arduino15/packages/SPRESENSE/tools/spresense-sdk/2.2.1/spresense/release/nuttx/include/inttypes.h:185:31: error: unknown type name 'wchar_t'
 intmax_t  wcstoimax(FAR const wchar_t *nptr, FAR wchar_t **endptr, int base);
                               ^
/home/guberti/.arduino15/packages/SPRESENSE/tools/spresense-sdk/2.2.1/spresense/release/nuttx/include/inttypes.h:185:50: error: unknown type name 'wchar_t'
 intmax_t  wcstoimax(FAR const wchar_t *nptr, FAR wchar_t **endptr, int base);
                                                  ^
/home/guberti/.arduino15/packages/SPRESENSE/tools/spresense-sdk/2.2.1/spresense/release/nuttx/include/inttypes.h:186:31: error: unknown type name 'wchar_t'
 uintmax_t wcstoumax(FAR const wchar_t *nptr, FAR wchar_t **endptr, int base);
                               ^
/home/guberti/.arduino15/packages/SPRESENSE/tools/spresense-sdk/2.2.1/spresense/release/nuttx/include/inttypes.h:186:50: error: unknown type name 'wchar_t'
 uintmax_t wcstoumax(FAR const wchar_t *nptr, FAR wchar_t **endptr, int base);
                                                  ^

You can also use this Arduino script to reproduce the issue.

Solution

This issue arises because inttypes.h cannot find where wchar_t is defined. It tries to import stddef.h for this purpose:

https://github.com/sonydevworld/spresense-nuttx/blob/5c65b4d1e49add94270d8c515b85534559dd9fb8/include/inttypes.h#L39-L43

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <stddef.h> /* for wchar_t */

However, for reasons unknown to me stddef.h does not define wchar_t. There's a comment saying that it should, so the logical solution seems to be moving the definition of wchar_t from sys/types.h to stddef.h.

https://github.com/sonydevworld/spresense-nuttx/blob/5c65b4d1e49add94270d8c515b85534559dd9fb8/include/stddef.h#L90-L93

/*
 * NOTE: Currently the type definitions of ptrdiff_t, wchar_t, and size_t are
 *     in sys/types.h but should be moved here sometime.
 */

[SPRESENSE]

@guberti
Thank you for reporting the issue.

This has been already resolved in the following commit on the develop branch, and will be released in the next official version.
sonydevworld/spresense-nuttx@e99e185#diff-18fc24aec5247a51ba32867677c04c53a35eda8f3407f7d94c55318867990088

Thanks.

[SPRESENSE]

SDK v2.3 has been released and this issue has been resolved.