by Harold Ancell
This SRFI is currently in withdrawn status. Here is an explanation of each status that a SRFI can hold. To provide input on this SRFI, please send email to
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author's summary of reasons for withdrawal: As thoroughly discussed on the mailing list, a simple Scheme level API like the one proposed is unsatisfactory because a Scheme implementation can run arbitrary code that might set errno between any of 1) manually setting it, 2) a POSIX call possibly setting it, and 3) retrieving its value. This, along with EINTR loops (see the Worse is Better essay) need to be done at a low level, and no one has been able to come up with a suitable standard and universal high level API for any of this.
The majority of POSIX system and library calls
errno to discern the specific cause
of an error, and some require setting it to 0 before being called.
This SRFI specifies procedures to both retrieve its value, and to
The POSIX lvalue
implemented as "a macro or an identifier declared with external
linkage". It does not fit into the paradigm of
autogenerating FFIs such as Chibi Scheme's, and for the latter must
be hand coded. Its value is required when using SRFI 198
POSIX system call exceptions, which does not
provide a procedure to get its value. This SRFI will allow many
implementers of POSIX interfaces to focus on their
particular system or library calls of interest without also
errno procedures or importing them
from another more general library.
(errno)→ exact integer (procedure)
Returns the current value of
(errno) ⇒ 2
(set-errno! errno)→ undefined (procedure)
Sets the current value of
errno, where the argument
errno is an exact integer.
(errno) ⇒ 2 (set-errno! 0) (errno) ⇒ 0
To be supplied for Chibi Scheme from its SRFI 170 sample implementation.
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