Compile error in Zephyr, can not find c funtion even include the head files

[Yanpengwu]

Hi Support team,

I'm compiling some c code with ncs v2.5.1,  the include files are:

#include <time.h>

#include <sys/time.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdbool.h>

But there are some compiling errors:

(1)

C:/dataLogger/hello_world/src/remote/tahu/tahu.c: In function 'set_propertyvalue':
C:/dataLogger/hello_world/src/remote/tahu/tahu.c:104:45: warning: implicit declaration of function 'strndup'; did you mean 'strncmp'? [-Wimplicit-function-declaration]
104 | propertyvalue->value.string_value = strndup(value, size);
| ^~~~~~~
| strncmp

(2) 

C:/dataLogger/hello_world/src/remote/tahu/tahu.c: In function 'get_current_timestamp':
C:/dataLogger/hello_world/src/remote/tahu/tahu.c:341:5: warning: implicit declaration of function 'clock_gettime' [-Wimplicit-function-declaration]
341 | clock_gettime(CLOCK_REALTIME, &ts);
| ^~~~~~~~~~~~~

Why I include the right header files, but still can not find the function strndup() and clock_gettime() in Zephyr, should add some configuration in prj.conf?

Could you help give some hints? Thank you very much.

Best regards,

Yanpeng Wu.

[Yanpengwu]

Update: When I config 'CONFIG_POSIX_API=y', the error of clock_gettime() disappeared.

But the errors of strdup and strndup still there. I found there is a Issue 22464 strdup function added to minimal C library #22491 and said the strdup was added into Zephyr. I'm using ncs v2.5.1, should I add some configuration for this?

Thank you very much.