mbedtls redefined warnings
AxelLin opened this issue · 2 comments
When I build with esp-idf CONFIG_MBEDTLS_ROM_MD5=y, I got below redefined warnings:
[944/1039] Building C object esp-idf/main/CMakeFiles/anjay.dir/anjay/deps/avs_commons/src/stream/md5/avs_stream_mbedtls.c.obj
/home/axel/esp/lwm2m/Anjay-esp32-client/main/anjay/deps/avs_commons/src/stream/md5/avs_stream_mbedtls.c:41: warning: "mbedtls_md5_update" redefined
# define mbedtls_md5_update mbedtls_md5_update_ret
In file included from /home/axel/esp/esp-idf/components/mbedtls/mbedtls/include/mbedtls/md5.h:94,
from /home/axel/esp/lwm2m/Anjay-esp32-client/main/anjay/deps/avs_commons/src/stream/md5/avs_stream_mbedtls.c:23:
/home/axel/esp/esp-idf/components/mbedtls/port/include/md5_alt.h:34: note: this is the location of the previous definition
#define mbedtls_md5_update esp_md5_update
/home/axel/esp/lwm2m/Anjay-esp32-client/main/anjay/deps/avs_commons/src/stream/md5/avs_stream_mbedtls.c:42: warning: "mbedtls_md5_finish" redefined
# define mbedtls_md5_finish mbedtls_md5_finish_ret
In file included from /home/axel/esp/esp-idf/components/mbedtls/mbedtls/include/mbedtls/md5.h:94,
from /home/axel/esp/lwm2m/Anjay-esp32-client/main/anjay/deps/avs_commons/src/stream/md5/avs_stream_mbedtls.c:23:
/home/axel/esp/esp-idf/components/mbedtls/port/include/md5_alt.h:35: note: this is the location of the previous definition
#define mbedtls_md5_finish esp_md5_finish
Note, CONFIG_MBEDTLS_ROM_MD5 is default y.
This stems from some API changes over the history of Mbed TLS:
- Before Mbed TLS 2.7, there were only functions such as
mbedtls_md5_starts(), which returnedvoid - In Mbed TLS 2.7, these functions got deprecated, with new APIs called e.g.
mbedtls_md5_starts_ret()added, able to return an error code asint - In Mbed TLS 3.0, the old deprecated APIs got removed, and the
*_ret()APIs have been renamed to the names identical to the old pre-2.7 function names
avs_commons uses the Mbed TLS 3.0 APIs, and includes these #defines to bridge the API differences between versions and stay compatible with Mbed TLS 2.x, including the pre-2.7 versions.
These macros seem to conflict with some macros in ESP-IDF, but we have checked the consequences of that and verified that this is harmless.
The warnings will almost certainly disappear once ESP-IDF is updated to use Mbed TLS 3.x. Due to that, the harmlessness of the warning and the fact that it comes from compatibility code that affects platforms other than ESP-IDF as well, we decided to just ignore the issue and let the warning be reported.