Compilare: user.c: In function ‘main’: user.c:35:9: warning: implicit declaration of function ‘exit’ [-Wimplicit-function-declaration] exit(1); ^ user.c:35:9: warning: incompatible implicit declaration of built-in function ‘exit’ [enabled by default] user.c:41:9: warning: incompatible implicit declaration of built-in function ‘exit’ [enabled by default] exit(1); ^ user.c:53:9: warning: implicit declaration of function ‘strdup’ [-Wimplicit-function-declaration] c=strdup(cuv); ^ user.c:53:10: warning: assignment makes pointer from integer without a cast [enabled by default] c=strdup(cuv); ^ user.c:73:14: warning: assignment makes pointer from integer without a cast [enabled by default] c=strdup(cuv); ^ user.c:28:9: warning: unused variable ‘k’ [-Wunused-variable] int k; ^ user.c:49:14: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(s,2014,f); ^ user.c:62:19: warning: ‘ok’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(ok){fputs(cap,g);ok=0;} ^ In file included from /usr/include/stdio.h:934:0, from user.c:1: In function ‘fgets’, inlined from ‘main’ at user.c:49:14: /usr/include/i386-linux-gnu/bits/stdio2.h:253:2: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [enabled by default] return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^