Created
May 27, 2018 19:09
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Defer cleanup for C (gcc and llvm)
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#define DEFER_MERGE(a,b) a##b | |
#define DEFER_VARNAME(a) DEFER_MERGE(defer_scopevar_, a) | |
#define DEFER_FUNCNAME(a) DEFER_MERGE(defer_scopefunc_, a) | |
#define DEFER(BLOCK) void DEFER_FUNCNAME(__LINE__)(int *a) BLOCK; __attribute__((cleanup(DEFER_FUNCNAME(__LINE__)))) int DEFER_VARNAME(__LINE__) | |
// Usage: | |
/* | |
void dosomething() | |
{ | |
char* data = malloc(100); | |
DEFER({ free(data); }); | |
dosomethingwith(data); | |
} | |
*/ |
I'm not sure, I have a different piece of code utilizing this in my libwire wire_defer.h but that code is marked GCC only. I don't remember why is that anymore.
compiles using clang ... but "disappears" upon execution?
Try this https://godbolt.org/z/6Y8Ys4dPo
Any C version and any compiler.
Nice! You can add __attribute__((unused))
before the int *a
parameter to get rid of the unused-parameter warning:
...
#define DEFER(BLOCK) void DEFER_FUNCNAME(__LINE__)(__attribute__((unused)) int *a) BLOCK; __attribute__((cleanup(DEFER_FUNCNAME(__LINE__)))) int DEFER_VARNAME(__LINE__)
Now simpler to re-use: https://godbolt.org/z/zsYre5Kfj
@sinecode
Did you manage to get rid of the warning: ISO C forbids nested functions [-Wpedantic]
warning?
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clang 10.0.0
I get: "Function definition is not allowed here"? Perhaps nested functions need some switch for clang?