path: root/builtin/fetch-pack.c
diff options
authorSZEDER Gábor <>2019-01-17 01:29:09 (GMT)
committerJunio C Hamano <>2019-01-17 19:13:38 (GMT)
commit764473d25772aeb6e1f02743bc13a6da8eb18cc3 (patch)
tree9aa91ba9ded95d56d630405e1931f5a483fca9b6 /builtin/fetch-pack.c
parent268fbcd172cdb306e8a3e7143cc16677c963d6cd (diff)
compat/obstack: fix -Wcast-function-type warnings
GCC 8 introduced the new -Wcast-function-type warning, which is implied by -Wextra (which, in turn is enabled in our DEVELOPER flags). When building Git with GCC 8 and this warning enabled on a non-glibc platform [1], one is greeted with a screenful of compiler warnings/errors: compat/obstack.c: In function '_obstack_begin': compat/obstack.c:162:17: error: cast between incompatible function types from 'void * (*)(long int)' to 'struct _obstack_chunk * (*)(void *, long int)' [-Werror=cast-function-type] h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun; ^ compat/obstack.c:163:16: error: cast between incompatible function types from 'void (*)(void *)' to 'void (*)(void *, struct _obstack_chunk *)' [-Werror=cast-function-type] h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun; ^ compat/obstack.c:116:8: error: cast between incompatible function types from 'struct _obstack_chunk * (*)(void *, long int)' to 'struct _obstack_chunk * (*)(long int)' [-Werror=cast-function-type] : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size))) ^ compat/obstack.c:168:22: note: in expansion of macro 'CALL_CHUNKFUN' chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size); ^~~~~~~~~~~~~ <snip> 'struct obstack' stores pointers to two functions to allocate and free "chunks", and depending on how obstack is used, these functions take either one parameter (like standard malloc() and free() do; this is how we use it in 'kwset.c') or two parameters. Presumably to reduce memory footprint, a single field is used to store the function pointer for both signatures, and then it's casted to the appropriate signature when the function pointer is accessed. These casts between function pointers with different number of parameters are what trigger those compiler errors. Modify 'struct obstack' to use unions to store function pointers with different signatures, and then use the union member with the appropriate signature when accessing these function pointers. This eliminates the need for those casts, and thus avoids this compiler error. [1] Compiling 'compat/obstack.c' on a platform with glibc is sort of a noop, see the comment before '# define ELIDE_CODE', so this is not an issue on common Linux distros. Signed-off-by: SZEDER Gábor <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'builtin/fetch-pack.c')
0 files changed, 0 insertions, 0 deletions