Compilare: user.c: In function ‘main’: user.c:90:3: warning: implicit declaration of function ‘exit’ [-Wimplicit-function-declaration] exit(1); ^~~~ user.c:90:3: warning: incompatible implicit declaration of built-in function ‘exit’ user.c:90:3: note: include ‘<stdlib.h>’ or provide a declaration of ‘exit’ user.c:97:3: warning: incompatible implicit declaration of built-in function ‘exit’ exit(1); ^~~~ user.c:97:3: note: include ‘<stdlib.h>’ or provide a declaration of ‘exit’ user.c:100:2: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(ip, "%s", pattern); ^~~~~~~~~~~~~~~~~~~~~~~~~ user.c:101:2: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(ip, "%s", text); ^~~~~~~~~~~~~~~~~~~~~~