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authorJonathan Nieder <jrnieder@gmail.com>2011-03-08 02:33:44 -0600
committerJunio C Hamano <gitster@pobox.com>2011-03-08 12:02:31 -0800
commit26db0f2e3afc043e184a5e0ce5eb7c53aeb1f644 (patch)
tree2a3fb0dcbfac0afb11ed2e23b39c3f88a2f5cac4
parentebeb60900fbab569ed14f710a0a1abb1637ec792 (diff)
downloadgit-26db0f2e3afc043e184a5e0ce5eb7c53aeb1f644.tar.gz
git-26db0f2e3afc043e184a5e0ce5eb7c53aeb1f644.tar.xz
compat: fall back on __va_copy if available
Since an obvious implementation of va_list is to make it a pointer into the stack frame, implementing va_copy as "dst = src" will work on many systems. Platforms that use something different (e.g., a size-1 array of structs, to be assigned with *(dst) = *(src)) will need some other compatibility macro, though. Luckily, as the glibc manual hints, such systems tend to provide the __va_copy macro (introduced in GCC in March, 1997). By using that if it is available, we can cover our bases pretty well. Discovered by building with CC="gcc -std=c89" on an amd64 machine: $ make CC=c89 strbuf.o [...] strbuf.c: In function 'strbuf_vaddf': strbuf.c:211:2: error: incompatible types when assigning to type 'va_list' from type 'struct __va_list_tag *' make: *** [strbuf.o] Error 1 Explained-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--git-compat-util.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/git-compat-util.h b/git-compat-util.h
index 00d41e4f0..f4cb0a9b0 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -536,7 +536,16 @@ void git_qsort(void *base, size_t nmemb, size_t size,
#endif
#ifndef va_copy
-#define va_copy(dst,src) (dst) = (src)
+/*
+ * Since an obvious implementation of va_list would be to make it a
+ * pointer into the stack frame, a simple assignment will work on
+ * many systems. But let's try to be more portable.
+ */
+#ifdef __va_copy
+#define va_copy(dst, src) __va_copy(dst, src)
+#else
+#define va_copy(dst, src) ((dst) = (src))
+#endif
#endif
/*