Greetings,

The current architecture-specific type definitions 
(arch/*/bits/alltypes.h) seem to entail the following inconsistent 
signed/unsigned types:

type      x86_64        i386
-------------------------------
uid_t     unsigned      signed
gid_t     unsigned      signed
dev_t     unsigned      signed
clock_t   signed        unsigned

For *uid_t* and *gid_t*, the GNU documentation specifies /_unsigned int_://
//http://www.gnu.org/software/libc/manual/html_node/Reading-Persona.html#index-uid_005ft-3309/

For *dev_t*, the specification requires /_an integer type no narrower 
than int//_/: and given the value it is expected to hold (file device 
numbers), making it /_unsigned_/ seems to be the correct choice.
/http://www.gnu.org/software/libc/manual/html_node/Attribute-Meanings.html#index-dev_005ft-1500/

*clock_t* is defined as the value returned by clock(), and the manual 
page states that  "if the processor time used is not available or its 
value cannot be represented, the function returns the value (clock_t) 
-1."  This in turn suggests that clock_t should be a _signed_ type.
/http://www.gnu.org/software/libc/manual/html_node/CPU-Time.html#index-clock_005ft-2607

/As an additional reference, attached is the output generated by 
musl-alltypes (posted on April 18) for the above architectures.
/
/Best regards,
Zvi