diff options
Diffstat (limited to 'src/glsl/glcpp/README')
| -rw-r--r-- | src/glsl/glcpp/README | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/src/glsl/glcpp/README b/src/glsl/glcpp/README index 0b5ef508ce..9cc00e9275 100644 --- a/src/glsl/glcpp/README +++ b/src/glsl/glcpp/README @@ -29,4 +29,27 @@ The __LINE__ and __FILE__ macros are not yet supported. A file that ends with a function-like macro name as the last non-whitespace token will result in a parse error, (where it should be -passed through as is).
\ No newline at end of file +passed through as is). + +Known deviations from the specification +--------------------------------------- +As mentoned above, the GLSL specification (as of 1.30.10) is fairly +vague on some aspects of the preprocessor, and we've been using C99 to +fill in details. Here is a list of cases where we have deviated from +the behavior specified in C99 to obtain better compatibility with +other GLSL implementations: + + * Redefining a macro with a different value + + C89 says that a macro "may be redefined ... provided that the + second definition [is equivalent]" (Section 3.8.3 Macro + Replacement/constraints) + + C99 is even more explicit, saying tthat a macro "shall not be + redefined by another #define preprocessing directive unless the + second definition [is equivalent]" (Section 6.10.3 Macro + Replacement/Constraints) + + In spite of this, glcpp emits a warning rather than an error for + non-equivalent redefinition of macros since this matches the + behavior of other, widely-used implementations. |