linux - Where can I find the definition for a system call parameter? -

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in ioctl man page defines:

int ioctl(int d,int request,...);

for example:

ioctl(fd,fionread,&nread);

where can find fionread information in linux? information defined? how many types there this?

in general, man page of system call (man 2 ioctl — section 2 system calls) right place.

ioctl special case because point of system call allow applications send commands devices don't fit in general mold. documentation of parameters not in documentation of ioctl, in documentation of device drivers. man pages devices in section 4 (or section 7 on unix variants).

on linux, ioctl(2) man page references ioctl_list(2) contains summary of common ioctl types. there more documentation ioctls in device man pages such tty_ioctl(4) (terminals — that's fionread used for) , sd(4) (disks scsi-like interface). more ioctl documented in kernel documentation, example cd drives. many drivers, linux lacks documentation , need refer kernel source code or headers (search under /usr/include , hope you'll find comments).


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