prog.c: In function ‘main’:
prog.c:11:5: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &size);
^~~~~~~~~~~~~~~~~~
prog.c:16:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%s", strings[i]);
^~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/ld: /home/w9Ju60/cc30PTFC.o: in function `main':
prog.c:(.text.startup+0x7c): undefined reference to `sort_by_length'
collect2: error: ld returned 1 exit status