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libakgl/include/akgl/error.h
Andrew Kesterson e4aa6a5084
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Take libakerror 2.0.1 and drop the workaround it makes obsolete
Every libakgl test suite could report success while failing. libakerror's
default unhandled-error handler ended in exit(errctx->status), an exit
status is one byte wide, and libakgl's band starts at 256 -- so
AKGL_ERR_SDL, the most common failure a library built on SDL can have,
exited 0 and CTest recorded a pass. tests/character.c aborted at its
second of four tests on a bad renderer and was green for months.

0.5.0 worked around that here with TEST_TRAP_UNHANDLED_ERRORS() in
tests/testutil.h, and TODO.md ended the entry saying any consumer's
suites have the same problem and it was worth raising upstream. It was.
2.0.1 fixes it at the source: akerr_exit() owns the mapping and the
default handler calls it, so 0 exits 0, 1 through 255 exit themselves,
and anything else exits AKERR_EXIT_STATUS_UNREPRESENTABLE (125). The
trap and its 21 call sites are gone.

Verified by putting the original failure back rather than by reading the
release notes: a FAIL_BREAK(AKGL_ERR_SDL) in tests/character.c's main
exits 125 and CTest reports a failure. A standalone consumer raising the
same status unhandled exits 125 where it exited 0 before.

tests/actor.c installs its own handler and called exit(errctx->status)
from it, which is the same defect one layer up. It calls akerr_exit()
now.

2.0.0 also makes the error pool and the status registry thread safe,
which libakgl needs more than it knew: audio_stream_callback raises
error contexts on SDL's audio thread. With an unlocked pool that
callback and the main thread could scan AKERR_ARRAY_ERROR at the same
time and be handed the same slot. The comment there says so.

This is a hard dependency floor, not a preference. 2.0.0 moved
__akerr_last_ignored to thread-local storage and made akerr_next_error()
return a context that already holds its reference, and both expand at
libakgl's call sites -- and at a consumer's, because akerror.h is part
of libakgl's public interface. Mixing headers and libraries across that
line double-counts every reference and never returns a pool slot. The
soname moved to libakerror.so.2; include/akgl/error.h now also feature-
tests AKERR_EXIT_STATUS_UNREPRESENTABLE, which is the narrowest probe
for 2.0.1 since libakerror publishes no version macro.

0.7.0 for that reason: libakgl's own ABI is unchanged, but the one it
re-exports through its headers is not.

TODO.md records the pkg-config gap this makes sharper -- akgl.pc names
no dependencies at all, so nothing tells a pkg-config consumer which
libakerror it needs.

Clean build, 26/26 ctest, memcheck clean, warning-clean at -Wall
-Werror. libakgl.so.0.7 links libakerror.so.2.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B8T5FAYXE8HEJqFLCYwNNc
2026-08-01 13:05:43 -04:00

100 lines
5.1 KiB
C

/**
* @file error.h
* @brief Declares the public error API.
*/
#ifndef _AKGL_ERROR_H_
#define _AKGL_ERROR_H_
#include <akerror.h>
/*
* libakerror 1.0.0 is the floor. That release moved the status-name table into a
* private registry -- AKERR_MAX_ERR_VALUE and __AKERR_ERROR_NAMES are gone, the
* registry entry points raise akerr_ErrorContext * instead of returning int, and
* the library gained an soname -- so a translation unit that pairs this header
* with a pre-1.0.0 akerror.h is an ABI mismatch, not just a compile problem.
*
* libakerror publishes no version macro, so this feature-tests on
* AKERR_FIRST_CONSUMER_STATUS, which that release introduced, rather than on a
* version number that does not exist. Without the guard an embedded build is
* fine but a stale installed header fails much further in, on the AKGL_ERR_*
* codes below and again inside src/heap.c.
*
* See deps/libakerror/UPGRADING.md.
*/
#ifndef AKERR_FIRST_CONSUMER_STATUS
#error "libakgl requires libakerror >= 2.0.1: the akerror.h on the include path predates the status registry. Rebuild and reinstall libakerror."
#endif
// 2.0.0 is an ABI break -- akerr_next_error() returns a context that already
// holds its reference, and __akerr_last_ignored is thread-local -- and both of
// those expand at *this* library's call sites through IGNORE and the FAIL
// macros. A libakgl built against a 1.x header and linked against 2.x
// double-counts every reference and never returns a slot to the pool. The
// soname moved to libakerror.so.2 so the two cannot be mixed by accident, but
// the header can still be stale in an install tree, so check it here too.
//
// AKERR_EXIT_STATUS_UNREPRESENTABLE arrived in 2.0.1 and is the narrowest thing
// to probe for: libakerror publishes no version macro.
#ifndef AKERR_EXIT_STATUS_UNREPRESENTABLE
#error "libakgl requires libakerror >= 2.0.1: the akerror.h on the include path predates akerr_exit(). Rebuild and reinstall libakerror."
#endif
// Silences -Wformat-truncation on a string concatenation that genuinely may not
// fit -- e.g. joining two PATH_MAX strings into one AKGL_MAX_STRING_LENGTH
// buffer. The line has to be drawn somewhere or the buffers grow forever to
// keep the compiler happy.
//
// **Nothing in libakgl uses these any more.** Both sites -- the path join in
// akgl_path_relative and the tileset image join in
// akgl_tilemap_load_layer_image -- now go through aksl_snprintf, which raises
// AKERR_OUTOFBOUNDS on truncation instead. That is the better answer: the
// compiler was right both times, and silencing it left the truncation
// happening and unreported. Kept because they are public and a consumer may
// have them; see TODO.md.
#define DISABLE_GCC_WARNING_FORMAT_TRUNCATION \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wformat-truncation\"")
#define RESTORE_GCC_WARNINGS \
_Pragma("GCC diagnostic pop")
// libakerror reserves statuses 0-255 for the host's errno values and its own
// AKERR_* codes; consumers allocate from AKERR_FIRST_CONSUMER_STATUS upward.
// These are fixed offsets from that base rather than from AKERR_LAST_ERRNO_VALUE
// so that a libc which grows an errno cannot move them out from under us.
//
// akgl_error_init() reserves this whole band in one call and registers a name
// for every code below. Add a code here and you must name it there, or it
// prints as "Unknown Error" in every stack trace that carries it.
#define AKGL_ERR_OWNER "libakgl"
#define AKGL_ERR_BASE AKERR_FIRST_CONSUMER_STATUS
#define AKGL_ERR_SDL (AKGL_ERR_BASE + 0) /**< An SDL call failed; the message carries SDL_GetError() */
#define AKGL_ERR_REGISTRY (AKGL_ERR_BASE + 1) /**< A registry property or lookup operation failed */
#define AKGL_ERR_HEAP (AKGL_ERR_BASE + 2) /**< A heap pool has no free object left to hand out */
#define AKGL_ERR_BEHAVIOR (AKGL_ERR_BASE + 3) /**< A component did not behave the way its contract requires */
#define AKGL_ERR_LOGICINTERRUPT (AKGL_ERR_BASE + 4) /**< Actor logic is telling the physics simulator to skip it */
// One past the last libakgl status. The reservation is all-or-nothing -- a
// subset or superset of an existing one is refused -- so this must stay one
// past the highest code above.
#define AKGL_ERR_LIMIT (AKGL_ERR_BASE + 5)
#define AKGL_ERR_COUNT (AKGL_ERR_LIMIT - AKGL_ERR_BASE)
/**
* @brief Claim the libakgl status band and register a name for every code in it.
*
* Call this before anything else in libakgl. Every other subsystem raises
* AKGL_ERR_* codes, and a code raised before this runs carries no name into its
* stack trace. Repeating the call is a no-op, so a program that cannot order its
* initialization precisely may call it more than once.
*
* @throws AKERR_STATUS_RANGE_OVERLAP When another component already owns part of the band.
* @throws AKERR_STATUS_RANGE_FULL When libakerror has no reservation slots left.
* @throws AKERR_STATUS_NAME_FULL When libakerror's name registry is full.
*/
akerr_ErrorContext AKERR_NOIGNORE *akgl_error_init(void);
#endif // _AKGL_ERROR_H_