nanogui: problems reading the buttons on the helio in VR Linux
Subject:
Re: problems reading the buttons on the helio in VR Linux
From:
Jordan Crouse ####@####.####
Date:
29 Dec 2000 14:51:36 -0000
Message-Id: <3A4CB450.1FF9AFC4@censoft.com>
Robert -
Toss in a perror() function when the open fails, which will report the
error that was passed back from open().
That will tell you right away whats wrong.
Jordan
Robert Hartley wrote:
>
> Hello,
>
> I whipped up the attached test file to try reading the button keys on
> the Helio running VR Linux from TVT. (pocketlinux)
>
> It keeps telling me that it cannot open the file /dev/r39xxbuttons
>
> I tested the same file by creating a named pipe using mknod called
> /dev/r39xxbuttons on a standard RH v6.2 Intel system that worked.
>
> What am I doing wrong?
>
> (Is there already a process that has this file open?)
>
> thanks for your help,
>
> Robert
>
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> ------------------------------------------------------------------------
> /*
> Simple button test program built with the following two lines:
> mipsel-linux-gcc -static helio-test.c -o helio-test
> mipsel-linux-strip helio-test
> */
> #include <stdio.h>
> #include <fcntl.h>
>
> char *button_fn = "/dev/r39xxbuttons";
> char ch;
>
> int main(int argc, char *argv[])
> {
> int fd = open(button_fn, O_RDONLY);
>
> if(fd == -1)
> {
> fprintf(stderr, "Unable to open file: %s\n", button_fn);
> exit(0);
> }
>
> while(read(fd, &ch, 1) > 0)
> {
> fprintf(stderr, "ch = %c = (int) %d\n", ch, (int) ch);
> }
>
> close(fd);
> fprintf(stderr, "Finished reading.\n");
>
> } /* main() */
>
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