cannot convert to a pointer type socket programming in C

Question

I am a beginner with sockets in C and trying to develop my first application this is a portion of the client code and it is giving me an error
the error is caused by the line indicated below.

    int sockfd = 0;  

char fromServer[MAXSIZE];

char * fromClient;

fromClient=(char*)malloc(MAXSIZE * sizeof(char));



struct sockaddr_in  remoteServAddr;
    sockfd  = Socket(AF_INET,SOCK_DGRAM,0);

   }
   int n;

   printf(">>");

   scanf("%s",&fromClient); //the error is on this line 

   sendto(sockfd,fromClient,MAXSIZE,0,(SA*)remoteServAddr,sizeof(remoteServAddr));

UPDATE: the error is fixed thank you

You might like to accept the answer that solved your problem, by clicking the answer's check-mark. — alk
– alk, Commented Dec 28, 2013 at 9:19

David Ranieri · Accepted Answer · 2013-12-28 09:10:43Z

3

char * fromClient;

fromClient=(char*)malloc(MAXSIZE * sizeof(char))
/* no need to cast, check the result, and sizeof(char) is always 1 */
...
scanf("%s",&fromClient);
/* scanf expects a pointer and fromClient is already a pointer */

should be

scanf("%s", fromClient);

Anyway, use fgets to prevent buffer overflows:

char *fromClient, *pos;

fgets(fromClient, MAXSIZE, stdin);
if ((pos = strchr(fromClient, '\n')) != NULL)
    *pos = '\0';

EDIT (as suggested by @egur):

And in sendto:

dest_addr: Points to a sockaddr structure containing the destination address. The length and format of the address depend on the address family of the socket.

(SA*)remoteServAddr

should be

(SA*)&remoteServAddr

(assuming that SA is an alias for struct sockaddr)

edited Dec 28, 2013 at 9:10

answered Dec 28, 2013 at 8:29

David Ranieri

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2 Comments

alk Over a year ago

@user3108337 Are you sure?

user3108337 Over a year ago

@Alter Mann this is how it looks now ===> char * fromClient; fromClient= malloc(MAXSIZE); fgets(fromClient, MAXSIZE, stdin); yes I am 31:41: error: cannot convert to a pointer type

egur · Accepted Answer · 2013-12-28 08:27:37Z

1

scanf("%s",&fromClient);

-->

scanf("%s", fromClient); // fromClient is already a char*

answered Dec 28, 2013 at 8:27

egur

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1 Comment

user3108337 Over a year ago

char * fromClient; fromClient= malloc(MAXSIZE); scanf("%s", fromClient); this still gives the same error

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