gethostname() function problems

[koumodaki]

I am having trouble with gethostname(). The code compiles correctly but the function returns an unknown error. I have compiled on VC6 and .Net2005 platforms. While in VC6, the buffer remains empty, in .Net2005, it gives me unknown error. Why does this occur? char myname[256]; memset((void*)myname,0,sizeof(myname); if(!gethostname(myname, sizeof(myname))) { int _temp = WSAGetLastError(); if(_temp == WSAEFAULT) MessageBox(NULL,"Socket creation failed; Attempt to get host name failed; WSAEFAULT ","Lamia",MB_OK);/* who are we? */ if(_temp == WSANOTINITIALISED) MessageBox(NULL,"Socket creation failed; Attempt to get host name failed; WSANOTINITIALISED ","Lamia",MB_OK); if(_temp == WSAENETDOWN) MessageBox(NULL,"Socket creation failed; Attempt to get host name failed; WSAENETDOWN ","Lamia",MB_OK); if(_temp == WSAEINPROGRESS) MessageBox(NULL,"Socket creation failed; Attempt to get host name failed; WSAEINPROGRESS ","Lamia",MB_OK); else MessageBox(NULL,"Socket creation failed; Attempt to get host name failed; error unknown","Lamia",MB_OK); }

[Saurabh Garg]

That is because there is no error!! You should look carefully at the value retuned by gethostname. From MSDN - "If no error occurs, gethostname returns zero. Otherwise, it returns SOCKET_ERROR and a specific error code can be retrieved by calling WSAGetLastError". So you should not use if(!gethostname()) it will go into if when function is successful. -Saurabh

[Jijo Raj]

Did you called WSAStartup() ? See the code block.

WORD wVersionRequested;
wVersionRequested = MAKEWORD( 2, 2 );

WSADATA wsaData;
int err = WSAStartup( wVersionRequested, &wsaData );

koumodaki wrote:

char myname[256]; memset((void*)myname,0,sizeof(myname);

BTW, one more suggestion, Instead of using memset, you can directly initialize the array. For instance,

char myname[256] = { 0 };

Regards, Jijo.

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[sudhir_Kumar]

The Problem is only with the intialization of WINSOCK.

Sudhir Kumar

[Hamid Taebi]

See Getting Addresses IP informations[^] if its helpfuls for you.