Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!rpi!leah!tmm33 From: tmm33@leah.Albany.Edu (Terry McCoy) Newsgroups: comp.unix.xenix Subject: getc help needed Message-ID: <2056@leah.Albany.Edu> Date: 27 Sep 89 14:26:28 GMT Reply-To: tmm33@leah.albany.edu.UUCP (Terry McCoy) Distribution: usa Organization: University at Albany, Computer Services Center Lines: 25 Does anyone known what would be needed to create a function similar to getc() that would return control to the calling function if the buffer was empty. My application running SCO XENIX 2.3 has opened a serial port and monitors it for incoming data. The data is coming as packets. I have tried using the system functions getc, fread and read but they all wait for data to arrive before returning control back to the calling function. I have looked at the getc function in the stdio.h header file and noticed that it calls a function _filbuf. I think that this function is located within the kernal and controls the pointers, flags and the counter within the structure FILE. Any information on how this function works or how I could tell if data has arrived at the serial port without waiting would be helpful. Terry McCoy SUNY Albany National Lightning Detection Network Research Foundation - State University of New York at Albany ------------------------------------------------------------------------------ internet: tmm33@leah.albany.edu Phone: (518) 442-4588 Snail Mail: Terry McCoy ES-235 SUNY Albany 1400 Washington Ave. Albany, NY 12222