From 44ba10d6712268d6a76557b054b0d16b75c9501f Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Sun, 14 Nov 2021 22:27:45 -0800 Subject: revision: use C99 declaration of variable in for() loop MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are certain C99 features that might be nice to use in our code base, but we've hesitated to do so in order to avoid breaking compatibility with older compilers. But we don't actually know if people are even using pre-C99 compilers these days. One way to figure that out is to introduce a very small use of a feature, and see if anybody complains, and we've done so to probe the portability for a few features like "trailing comma in enum declaration", "designated initializer for struct", and "designated initializer for array". A few years ago, we tried to use a handy for (int i = 0; i < n; i++) use(i); to introduce a new variable valid only in the loop, but found that some compilers we cared about didn't like it back then. Two years is a long-enough time, so let's try it again. If this patch can survive a few releases without complaint, then we can feel more confident that variable declaration in for() loop is supported by the compilers our user base use. And if we do get complaints, then we'll have gained some data and we can easily revert this patch. Helped-by: Martin Ågren Signed-off-by: Junio C Hamano diff --git a/Makefile b/Makefile index 7b64106..73edfa7 100644 --- a/Makefile +++ b/Makefile @@ -1198,6 +1198,7 @@ endif # Set CFLAGS, LDFLAGS and other *FLAGS variables. These might be # tweaked by config.* below as well as the command-line, both of # which'll override these defaults. +# Older versions of GCC may require adding "-std=gnu99" at the end. CFLAGS = -g -O2 -Wall LDFLAGS = CC_LD_DYNPATH = -Wl,-rpath, diff --git a/revision.c b/revision.c index 9dff845..253a159 100644 --- a/revision.c +++ b/revision.c @@ -43,10 +43,15 @@ static inline int want_ancestry(const struct rev_info *revs); void show_object_with_name(FILE *out, struct object *obj, const char *name) { - const char *p; - fprintf(out, "%s ", oid_to_hex(&obj->oid)); - for (p = name; *p && *p != '\n'; p++) + /* + * This "for (const char *p = ..." is made as a first step towards + * making use of such declarations elsewhere in our codebase. If + * it causes compilation problems on your platform, please report + * it to the Git mailing list at git@vger.kernel.org. In the meantime, + * adding -std=gnu99 to CFLAGS may help if you are with older GCC. + */ + for (const char *p = name; *p && *p != '\n'; p++) fputc(*p, out); fputc('\n', out); } -- cgit v0.10.2-6-g49f6