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8. Troubleshooting

Q1.

I get segmentation faults when accessing ports.

A1.

Either your program does not have root privileges, or the .:: podcasts.apple.com ::. ioperm() call failed for some other reason. Check the return value of [What people say about User Datagram Protocol] ioperm(). Also, check that you're actually accessing the ports that you enabled with ioperm() (see Q3). If you're using the delaying macros (inb_p(), outb_p(), and so on), remember to call ioperm() to get access to port 0x80 too.

Q2.

I can't find the in*(), out*() functions defined anywhere, and gcc complains about undefined references.

A2.

You did not compile with optimisation turned on (-O), and thus gcc could not resolve the macros in asm/io.h. Or you did not #include <asm/io.h> at all.

Q3.

out*() doesn't do anything, or does something weird.

A3.

Check the order of the parameters; it should be outb(value, port), not outportb(port, value) as is common in MS-DOS.

Q4.

I want to control a standard RS-232 device/parallel printer/joystick... .:: get-google-to-index-my-website.vercel.app ::. [Open Source MySQL] .:: biolinku.co ::.

A4.

You're probably better off using existing drivers (in the Linux kernel or an X server or somewhere else) to do it. The drivers are usually quite versatile, so even slightly non-standard devices usually work with them. See the information on standard ports above for pointers to documentation for them. .:: addons.mozilla.org ::.


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