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hack: make flexible union members work on gcc≤14 

In GCC <= 14, flexible arrays are not supported in unions because of a parserlimitation.

This is a hack that declares an anonymous struct, which itself can contain a flexible array but still be a member of a union. Another empty element is included because structs that only contain a flexible array are also invalid.
This commit is contained in:
Mohamed Gaber 2026-06-30 02:25:11 +03:00
parent e9dc6979e8
commit b4ebece2c9
No known key found for this signature in database
3 changed files with 21 additions and 8 deletions
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8
database/database.h.in
View File

@ -735,10 +735,10 @@ typedef struct
int prop_len; /* String length or number of values */ int prop_len; /* String length or number of values */
union { union {
Plane *prop_plane; /* For PROPERTY_TYPE_PLANE */ Plane *prop_plane; /* For PROPERTY_TYPE_PLANE */
int prop_integer[]; /* For PROPERTY_TYPE_INTEGER or _DIMENSION */ FLEX_UNION_MEMBER(int prop_integer[], 0); /* For PROPERTY_TYPE_INTEGER or _DIMENSION */
dlong prop_double[]; /* For PROPERTY_TYPE_DOUBLE */ FLEX_UNION_MEMBER(dlong prop_double[], 1); /* For PROPERTY_TYPE_DOUBLE */
char prop_string[]; /* For PROPERTY_TYPE_STRING, must be last in FLEX_UNION_MEMBER(char prop_string[], 2); /* For PROPERTY_TYPE_STRING, must be last in
* struct and union */ * struct and union */
} prop_value; } prop_value;
} PropertyRecord; } PropertyRecord;

8
utils/hash.h
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@ -34,10 +34,10 @@ typedef struct h1
char *h_pointer; /* Pointer to anything. */ char *h_pointer; /* Pointer to anything. */
struct h1 *h_next; /* Next element, zero for end. */ struct h1 *h_next; /* Next element, zero for end. */
union { union {
const char *h_ptr; /* One-word key value to identify entry. */ const char *h_ptr; /* One-word key value to identify entry. */
/* Following members must be the last part of the struct and union:*/ /* Following members must be the last part of the struct and union:*/
unsigned h_words[]; /* N-word key value. */ FLEX_UNION_MEMBER(unsigned h_words[], 0); /* N-word key value. */
char h_name[]; /* Text name of this entry. */ FLEX_UNION_MEMBER(char h_name[], 1); /* Text name of this entry. */
} h_key; } h_key;
} HashEntry; } HashEntry;

13
utils/magic.h
View File

@ -286,6 +286,19 @@ extern char AbortMessage[];
#endif #endif
#endif #endif
/*
* In GCC <= 14, flexible arrays are not supported in unions because of a parser
* limitation.
*
* This is a hack that declares an anonymous struct, which itself can contain
* a flexible array but still be a member of a union. Another empty element is
* included because structs that only contain a flexible array are also invalid.
*/
#define FLEX_UNION_MEMBER(member, member_no) struct {\
char __empty ## member_no [0]; member;\
}
/* ------------------ End of Machine Configuration Section ----------------- */ /* ------------------ End of Machine Configuration Section ----------------- */
#endif /* _MAGIC__UTILS__MAGIC_H */ #endif /* _MAGIC__UTILS__MAGIC_H */