C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Array of Pointers and Freeing problem          C++Talk.NET Forum Index -> C Language View previous topic :: View next topic   Author Message Guest Posted: Sat May 12, 2007 9:11 am    Post subject: Array of Pointers and Freeing problem hi, Following is problematic Code main() { char *ptr[1]={NULL}; ftn(ptr); } void ftn(**data) { *data=malloc(4); memset(*data,0,4); strcpy(*data,"HAI"); } Back to top Richard Heathfield Guest Posted: Sat May 12, 2007 9:11 am    Post subject: Re: Array of Pointers and Freeing problem anand1603 (AT) yahoo (DOT) com said: Quote: On May 12, 12:40 am, anand1...@yahoo.com wrote: hi, Following is problematic Code main() { char *ptr[1]={NULL}; ftn(ptr); printf("String is %s\n",*ptr) /*It PRints "HAI" -No Problem*/ if(*ptr !=NULL) free(*ptr); /*It Says Invalid Pointer*/ } void ftn(**data) { *data=malloc(4); memset(*data,0,4); strcpy(*data,"HAI"); }- hi, Please let me why the free is throwing "Inavild Pointer" Error. foo.c:2: warning: return-type defaults to `int' foo.c:2: warning: function declaration isn't a prototype foo.c: In function `main': foo.c:3: `NULL' undeclared (first use in this function) foo.c:3: (Each undeclared identifier is reported only once foo.c:3: for each function it appears in.) foo.c:3: initializer element is not computable at load time foo.c:3: (near initialization for `ptr[0]') foo.c:4: warning: implicit declaration of function `ftn' foo.c:5: warning: implicit declaration of function `printf' foo.c:7: parse error before `if' foo.c:10: warning: control reaches end of non-void function foo.c: At top level: foo.c:12: parse error before `*' foo.c:13: warning: function declaration isn't a prototype foo.c:13: warning: type mismatch with previous implicit declaration foo.c:4: warning: previous implicit declaration of `ftn' foo.c:13: warning: `ftn' was previously implicitly declared to return `int' foo.c: In function `ftn': foo.c:14: `data' undeclared (first use in this function) foo.c:14: warning: implicit declaration of function `malloc' make: *** [foo.o] Error 1 Sort those out, and come on back if you're still having trouble. -- Richard Heathfield "Usenet is a strange place" - dmr 29/7/1999 http://www.cpax.org.uk email: rjh at the above domain, - www. Back to top Richard Heathfield Guest Posted: Sat May 12, 2007 9:11 am    Post subject: Re: Array of Pointers and Freeing problem anand1603 (AT) yahoo (DOT) com said: Quote: hi, Following is problematic Code main() { char *ptr[1]={NULL}; ftn(ptr); } void ftn(**data) { *data=malloc(4); memset(*data,0,4); strcpy(*data,"HAI"); } You're right. The code is problematic. For one thing, it won't compile. -- Richard Heathfield "Usenet is a strange place" - dmr 29/7/1999 http://www.cpax.org.uk email: rjh at the above domain, - www. Back to top Guest Posted: Sat May 12, 2007 9:11 am    Post subject: Re: Array of Pointers and Freeing problem On May 12, 12:40 am, anand1...@yahoo.com wrote: Quote: hi, Following is problematic Code main() { char *ptr[1]={NULL}; ftn(ptr); printf("String is %s\n",*ptr) /*It PRints "HAI" -No Problem*/ if(*ptr !=NULL) free(*ptr); /*It Says Invalid Pointer*/ Quote: } void ftn(**data) { *data=malloc(4); memset(*data,0,4); strcpy(*data,"HAI"); }- hi, Please let me why the free is throwing "Inavild Pointer" Error. Your help is highly aprreciated. Regards Anand Back to top        C++Talk.NET Forum Index -> C Language All times are GMT Page 1 of 1 Powered by phpBB © 2001, 2006 phpBB Group