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SVR4 API Changes

The SVR4 API changes the size of a number of system structures to accommodate the changes in Expanded Fundamental Types. (Briefly, a number of fields, such as the user and group ID and device numbers are changed from 16 to 32 bits.) For driver work, the most important impact of these API changes is in the access to the major and minor numbers. The device number is now a 32-bit quantity, by changing the underlying type of the typedef dev_t. Access to the major and minor numbers can no longer be done with the 8-bit shift-and-mask technique common in prior versions of UNIX. (This is especially true as the split of the 32 bits between major and minor is a "hidden" parameter.) DDI defines a series of functions/macros to provide access to the major and minor numbers.


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