prog.c: In function ‘main’:
prog.c:5:3: warning: implicit declaration of function ‘prientf’ [-Wimplicit-function-declaration]
prientf("age에 저장된 값:%d\n",age);
^~~~~~~
/home/o2B4QR/ccOGtFqC.o: In function `main':
prog.c:(.text.startup+0x13): undefined reference to `prientf'
collect2: error: ld returned 1 exit status