我在调用
vendor\hisi\hi3861\hi3861\platform\os\Huawei_LiteOS\components\lib\libc\musl\include\time.h

文件中的strftime (char *__restrict, size_t, const char *__restrict, const struct tm *__restrict)时在编译时在链接的时候显示未定义：

coap_debug.c:(.text.coap_log_impl+0x15a): undefined reference to `strftime'

我猜这个应该是.h有声明 但是.c没实现，看这个目录海思应该是以lib开放，但我没找到对应的lib文件
，我觉得即使有这个lib文件应该也是不完整的

还有很多函数没有实现，如下编译报错，请问什么原因

coap_debug.c:(.text.print_readable.constprop.1+0x7c): undefined reference to __assert_fail' riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L106':
coap_debug.c:(.text.coap_log_impl+0xf4): undefined reference to stderr' riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L118':
coap_debug.c:(.text.coap_log_impl+0x15a): undefined reference to strftime' riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L0 ':
coap_debug.c:(.text.coap_log_impl+0x170): undefined reference to fprintf' riscv32-unknown-elf-ld: coap_debug.c:(.text.coap_log_impl+0x196): undefined reference to fprintf'
riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L112': coap_debug.c:(.text.coap_log_impl+0x1ba): undefined reference to fflush'
riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L0 ': coap_debug.c:(.text.coap_show_pdu+0x1fa): undefined reference to fprintf'
riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L154': coap_debug.c:(.text.coap_show_pdu+0x2ba): undefined reference to fprintf'
riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_debug.o): in function .L158': coap_debug.c:(.text.coap_show_pdu+0x38a): undefined reference to fprintf'
riscv32-unknown-elf-ld: ohos/libs/libcoap.a(coap_io.o): in function `.L0 ':