diff options
Diffstat (limited to 'include/symcat.h')
| -rw-r--r-- | include/symcat.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/include/symcat.h b/include/symcat.h index 3e27162b264..41589d42add 100644 --- a/include/symcat.h +++ b/include/symcat.h @@ -19,12 +19,16 @@ #ifndef SYM_CAT_H #define SYM_CAT_H -#if defined (__STDC__) || defined (ALMOST_STDC) +#if defined (__STDC__) || defined (ALMOST_STDC) || defined (HAVE_STRINGIZE) #define CONCAT2(a,b) a##b #define CONCAT3(a,b,c) a##b##c #define CONCAT4(a,b,c,d) a##b##c##d #define STRINGX(s) #s #else +/* Note one should never pass extra whitespace to the CONCATn macros, + e.g. CONCAT2(foo, bar) because traditonal C will keep the space between + the two labels instead of concatenating them. Instead, make sure to + write CONCAT2(foo,bar). */ #define CONCAT2(a,b) a/**/b #define CONCAT3(a,b,c) a/**/b/**/c #define CONCAT4(a,b,c,d) a/**/b/**/c/**/d @@ -35,6 +39,11 @@ #define XCONCAT3(a,b,c) CONCAT3(a,b,c) #define XCONCAT4(a,b,c,d) CONCAT4(a,b,c,d) +/* Note the layer of indirection here is typically used to allow + stringification of the expansion of macros. I.e. "#define foo + bar", "XSTRING(foo)", to yield "bar". Be aware that this only + works for __STDC__, not for traditional C which will still resolve + to "foo". */ #define XSTRING(s) STRINGX(s) #endif SYM_CAT_H |