On 01/25/2017 02:18 AM, David Guillen Fandos wrote:
Hello,
I wrote an app that was crashing in c-ares due to fds being bigger than
1024. While c-ares might be using around 30 fds it is unable to use fds
above 1024.
no, that's not a truth. you may use any socket number on all modern UNIX
systems. the only thing you need - you have to allocate enough memory
for fd_set. one more thing you have to know is still here. on Solaris
you may define the FD_SETSIZE preprocessor constant to any numer which
is big enough.
the sample C++ code (1st call prepare()):
class unx_fd_set_t {
char *Ptr;
size_t MFd;
long Psize;
size_t Sz;
void init0( size_t nSz ) {
char *nPtr = new char[ nSz ];
if( !nPtr )
d_exception_raise( "no enough memory" );
delete[] Ptr;
Sz = nSz;
Ptr = nPtr;
}
void init() {
// filled up to 32 bytes + 32 bytes gap
size_t nSz = (((MFd + 8)/8)/Psize + 1)*Psize;
if( nSz > Sz )
init0( nSz );
}
void prepare( size_t mFd ) {
if( mFd > MFd ) {
MFd = mFd;
init();
}
memset( Ptr, 0, Sz );
}
public:
unx_fd_set_t() : Ptr( 0 ), MFd( 0 ), Psize( sysconf( _SC_PAGESIZE )
), Sz( 0 ) {
if( Psize <= 0 ) Psize = 4096;
init();
memset( Ptr, 0, Sz );
}
~unx_fd_set_t() { delete[] Ptr; }
void set_fd( int fd ) { FD_SET( fd, (fd_set*)Ptr ); }
void clr_fd( int fd ) { FD_CLR( fd, (fd_set*)Ptr ); }
bool is_set( int fd ) { return FD_ISSET( fd, (fd_set*)Ptr ); }
fd_set *set() { return (fd_set *)Ptr; }
};
--
Yours sincerely, Eugeny.
GM of Enterprise Solutions Department
Doctor Web, Ltd.
http://www.drweb.com, +79119997425
