Tiny Core Base > Raspberry Pi

Disable blinking cursor in terminal from C program.

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Rich:
Hi AlexM

This looks wrong:

--- Code: ---console_fd = open(tty_n, O_RDWR);

if (!console_fd) {
    fprintf(stderr,"Could not open console.\n");
    exit(1);
}
--- End code ---

According to the man page:

--- Quote ---RETURN VALUE

       On success, open(), openat(), and creat() return the new file
       descriptor (a nonnegative integer).  On error, -1 is returned and
       errno is set to indicate the error.
--- End quote ---
Found here:
https://man7.org/linux/man-pages/man2/open.2.html#RETURN_VALUE

Your error test should probably look something like this:

--- Code: ---if (console_fd < 0)
{
    printf("Could not open console.\n%s\n", strerror(errno));
    exit(1);
}
--- End code ---

By the way, ttyname and ioctl both set  errno  when they fail if you want
a little more detail in your error messages:
https://man7.org/linux/man-pages/man3/ttyname.3.html#RETURN_VALUE
https://man7.org/linux/man-pages/man2/ioctl.2.html#RETURN_VALUE

AlexM:

--- Quote from: Rich on September 18, 2023, 09:09:36 PM ---This looks wrong:

--- Code: ---console_fd = open(tty_n, O_RDWR);

if (!console_fd) {
    fprintf(stderr,"Could not open console.\n");
    exit(1);
}
--- End code ---

--- End quote ---
Yes, you are absolutely right. Problem is in permissions and error code checking.

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