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implemented const_cast as a macro #7045

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implemented const_cast as a macro #7045

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a09a51b
implemented const_cast as a macro
badasahog Jun 4, 2025
49ddf38
Merge branch 'master' into constCastMacro
badasahog Jun 16, 2025
726b126
Merge branch 'master' into constCastMacro
badasahog Aug 19, 2025
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10 changes: 4 additions & 6 deletions src/fread.c
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Original file line number Diff line number Diff line change
Expand Up @@ -126,13 +126,11 @@ static void Field(FieldParseContext *ctx);
//=================================================================================================

/**
* Drops `const` qualifier from a `const char*` variable, equivalent of
* `const_cast<char*>` in C++.
* Drops `const` qualifier from any scalar object, equivalent of
* `const_cast` in C++.
*/
static char* const_cast(const char *ptr) {
union { const char *a; char *b; } tmp = { ptr };
return tmp.b;
}
#define const_cast(x) (((union{typeof(x) a; typeof(+(*(x)))* b;}){.a=(x)}).b)
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@Anirban166 Anirban166 Jun 26, 2025

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In the issue titled 'awful one liners don't improve readability or performance' (#6995) I see you wrote:

Collapsing everything into one line doesn't make the code run faster, the compiler is smart enough to sort it out.

I wonder what category this belongs to then 🤔

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@badasahog badasahog Jun 29, 2025 •
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A fair criticism!

The problem is, I don't think it's even possible to implement it differently since its a macro, and I think const_cast already has a clear enough meaning that the one liner isn't too bad here. It's clear what the code does.



/**
* Free any resources / memory buffers allocated by the fread() function, and
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