You're probably "Suffering from buffering". Plus the recommendataion is not to mix the sys* functions with the regular versions.

What do you get if you rewrite your print statement using syswrite() instead?

Update: Nevermind, I thought you were using print to write to the driver...

In reply to Re: Custom ioctl on Linux? by bot403
in thread Custom ioctl on Linux? by wjblack

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