i am having trouble in a program where i am using select command to monitor the pipe end in the parent .the pipe is used for the child to write nad the parent to read only .the read and write neds in the child and parent respectively , are closed .
now when the child dies , the parent end of the pipe becomes readable with 0 characters and i cannot read that and so apparantly (if pipes are buffered) the buffer does not clear and it remains readable thus making the select go into an infinite loop of continuously reading the pipe .
if anybody knows whats causing this please help me out .also if anybody knwos how to clear a pipe buffer that might also help fix the problem .
the code snippet is
if ( (pid= Fork() ) == 0) // FORKING CHILD PROCESS
{
close(pfd[0]); //CLOSE READ IN CHLD
dup2(pfd[1], 3); // DUPLICATE WRITE SOCKET
if (pfd[1]!= 3) close(pfd[1]); //CLOSE EXTRA SOCKET
switch(choice){
case 1: {execlp("xterm", "xterm", "-e", "./tcpcli01", str, (char *) 0);break;}
case 2: {execlp("xterm", "xterm", "-e", "./tcpcli02", str, (char *) 0);break;}
}
}
else { // inside parent
close (pfd[1]); //CLOSE WRITE AT PARENT
FD_ZERO(&rset);
FD_SET(pfd[0], &rset);
FD_SET(0, &rset);
maxfdp1 = max(pfd[0],0) + 1 ;
for( ; ; ){
allset = rset;
if( (n=select(maxfdp1, &allset, NULL, NULL, NULL)) <=0 ){// SELECT
if(errno==EINTR) {
close(pfd[0]);break;
}
else { printf("SELECT ERROR (NOT EINTR)\n");break;}
}

if (FD_ISSET(pfd[0], &allset)) { /* socket readable */
n2 = read(pfd[0], buf, MAXLINE);
if (n2 == 0)
FD_CLR(pfd[0], &rset);
else
write(1,buf,n2);
}

if (FD_ISSET(0, &allset)) { /* input is readable */
printf("write in the exec window please!!\n");
read(0,buf,MAXLINE);
}

}

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