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aaa6ac5fe1
Implement the error handling proposals from February 2022 on the
mercury-users list, and August 2022 on the mercury-reviews list.
We add io.system_error to the public interface of io.m
and document what its foreign representation is for each backend.
We allow io.error to optionally contain an io.system_error value,
and provide predicates to retrieve the io.system_error from an io.error.
The user may then inspect the system error via foreign code.
We also provide a predicate that takes an io.error and returns a name
for the system error it contains (if any). This makes it relatively easy
for Mercury programs to check for specific error conditions.
By returning platform-specific (actually, implementation-dependent)
error names, we are pushing the responsibility of mapping strings to
error conditions onto the application programmer. On the other hand, it
is not practical for us to map all possible system-specific error codes
to some common set of values. We could do it for a small set of common
error codes/exceptions, perhaps.
The standard library will construct io.error values containing
io.system_errors. However, we do not yet provide a facility for user
code to do the same.
library/io.m:
Move io.system_error to the public interface.
Change the internal representation of io.error to support containing
a io.system_error. An io.system_error may originate from an errno
value or a Windows system error code; the constructor distinguishes
those cases.
Add predicates to retrieve a system_error from io.error.
Add predicate to return the name of the system error in an io.error.
Replace make_err_msg with make_io_error_from_system_error.
Replace make_maybe_win32_err_msg with
make_io_error_from_maybe_win32_error.
Delete ML_make_err_msg and ML_make_win32_err_msg macros.
browser/listing.m:
library/bitmap.m:
library/dir.m:
library/io.call_system.m:
library/io.environment.m:
library/io.file.m:
library/io.text_read.m:
mdbcomp/program_representation.m:
Conform to changes.
Leave comments for followup work.
tools/generate_errno_name:
tools/generate_windows_error_name:
Add scripts to generate mercury_errno_name.c and
mercury_windows_error_name.c.
runtime/Mmakefile:
runtime/mercury_errno_name.c:
runtime/mercury_errno_name.h:
runtime/mercury_windows_error_name.c:
runtime/mercury_windows_error_name.h:
Add MR_errno_name() and MR_win32_error_name() functions,
used by io.m to convert error codes to string names.
tests/hard_coded/null_char.exp:
Update expected output.
12 lines
285 B
C
12 lines
285 B
C
// vim: ts=4 sw=4 expandtab ft=c
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// Copyright (C) 2022 The Mercury team.
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// This file is distributed under the terms specified in COPYING.LIB.
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#ifndef MERCURY_ERRNO_NAME_H
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#define MERCURY_ERRNO_NAME_H
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extern const char *MR_errno_name(int errnum);
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#endif // MERCURY_ERRNO_NAME_H
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