RE: source(builtin) and read(2)

[Hartmut Brandt]

On Tue, 3 Apr 2007, Schwarz, Konrad wrote:

SK>> -----Original Message-----
SK>> From: Geoff Clare [mailto:address@hidden 
SK>> Sent: Monday, April 02, 2007 10:22 AM
SK>> To: bug-gnulib; Matthew Woehlke; address@hidden
SK>> Subject: Re: source(builtin) and read(2)
SK>
SK>> I'll submit a defect report.
SK>
SK>Perhaps it would be possible to typedef ssize_t to ptrdiff_t at the same
SK>time (or eliminate ssize_t alltogether).
SK>
SK>There does not seem to be any worthwhile reason for separating the two:
SK>The only technical reason given for the existance of ssize_t is the
SK>ability to alias it with size_t when processing arguments with
SK><stdarg.h> -- which I consider of marginal importance at best; the C
SK>standards committee has certainly not made ssize_t part of the C
SK>standard.
SK>
SK>The argument that since ptrdiff_t is intended to represent the
SK>difference of pointers makes it somehow unsuitable to represent the
SK>result of read()/write() is missing the point: on any useful ABI,
SK>ptrdiff_t can represent the size of any object, can represent 0, and can
SK>represent -1, which is what read() and cousins require.

Please keep in mind, that ssize_t exists for a long time. It was already 
in sys/types.h Rev. 8.4 (1/21/94) of the BSD code (Rev. 1.1 of FreeBSDs 
types.h). I don't have the BSD repo at hand to track that back in the 
original sources. It is used all over the places so eliminating is is 
hardly a good idea. This would also have influence on printf's %z and so 
on.

harti