I am getting error as undefined reference how to resolve it

Question

this is the error i got

main.c:(.text+0x6c): undefined reference to `app_init'
main.c:(.text+0x88): undefined reference to `pthread_create'
main.c:(.text+0xa0): undefined reference to `ERROR'
main.c:(.text+0xb0): undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status
make: *** [all] Error 1

even i added header file and in compilation i added -lpthread.then also this error is comming;

Comments

What command is giving you this error?