tools/mksyscall: fix union illegal type for cast#18360
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zyfeier wants to merge 1 commit intoapache:masterfrom
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tools/mksyscall: fix union illegal type for cast#18360zyfeier wants to merge 1 commit intoapache:masterfrom
zyfeier wants to merge 1 commit intoapache:masterfrom
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Some compilers (e.g., Tasking) do not allow forced type casting of unions. Replace the direct cast with memcpy to copy the union parameter into a local variable, avoiding the illegal cast while preserving the correct behavior. Signed-off-by: zhangyuan29 <zhangyuan29@xiaomi.com>
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Area: Tooling
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simbit18
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anchao
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Feb 6, 2026
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| /* Fixed union illegal type for cast */ | ||
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| for (i = 0; i < nparms; i++) |
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Some compilers (e.g., Tasking) do not allow forced type casting of unions. Replace the direct cast with memcpy to copy the union parameter into a local variable, avoiding the illegal cast while preserving the correct behavior.
Note: Please adhere to Contributing Guidelines.
Summary
Some compilers (e.g., Tasking) do not allow forced type casting of unions in generated syscall stub files. The mksyscall tool previously generated code like (union_type)((uintptr_t)parm), which is illegal on strict compilers.
This patch replaces the direct union cast with memcpy to copy the uintptr_t parameter into a local union variable, avoiding the illegal cast while preserving correct behavior.
Changed file:
mksyscall.c
Impact
No breaking changes — only affects generated stub code for union-type parameters
Improves compiler compatibility (Tasking and other strict C compilers)
No functional behavior change at runtime
Testing
Build host: Ubuntu Linux x86_64
Target: Tasking compiler toolchain
Steps:
Configured NuttX with a board that uses syscalls with union parameters
Ran make to generate stub files via mksyscall
Verified generated STUB files no longer contain direct union casts
Verified generated code uses memcpy for union parameters
Build completed without illegal type for cast or incompatible types at assignment errors
Verification checklist:
Generated stub files compile without errors on Tasking compiler
No regression on GCC/Clang builds
Union parameter values correctly passed through syscall interface