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Full Discussion: Parent,child wait,signal
Top Forums Programming Parent,child wait,signal Post 302528276 by Corona688 on Monday 6th of June 2011 09:31:18 PM
Old 06-06-2011
read() isn't a string function. It doesn't give you a null terminator. You have to check its return value to see how much you read, and print it with write() fwrite() or the like.

Your program is still extremely incomplete, so I have no idea what you're writing to the fifo.

Also, I see you're using cygwin, not UNIX, so the behavior of this program may be very suspect in any case. Windows doesn't actually have named pipe files.

Last edited by Corona688; 06-06-2011 at 10:50 PM..
 

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WAIT(2) 							System Calls Manual							   WAIT(2)

NAME
wait - wait for process to terminate SYNOPSIS
wait(status) int *status; wait(0) DESCRIPTION
Wait causes its caller to delay until a signal is received or one of its child processes terminates. If any child has died since the last wait, return is immediate; if there are no children, return is immediate with the error bit set (resp. with a value of -1 returned). The normal return yields the process ID of the terminated child. In the case of several children several wait calls are needed to learn of all the deaths. If (int)status is nonzero, the high byte of the word pointed to receives the low byte of the argument of exit when the child terminated. The low byte receives the termination status of the process. See signal(2) for a list of termination statuses (signals); 0 status indi- cates normal termination. A special status (0177) is returned for a stopped process which has not terminated and can be restarted. See ptrace(2). If the 0200 bit of the termination status is set, a core image of the process was produced by the system. If the parent process terminates without waiting on its children, the initialization process (process ID = 1) inherits the children. SEE ALSO
exit(2), fork(2), signal(2) DIAGNOSTICS
Returns -1 if there are no children not previously waited for. ASSEMBLER
(wait = 7.) sys wait (process ID in r0) (status in r1) The high byte of the status is the low byte of r0 in the child at termination. WAIT(2)
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