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C Interop

Overview

One can write foreign function interfaces (FFIs) for C by preceding the function declaration with extern "C".

extern "C" fn my_ffi(...): type;

This prevents name mangling and forces the C Calling Convention.

Types like char are directly compatible with the C counterpart. The following C types are provided for writing FFIs:

Type	C counterpart
`c_int`	`int`
`c_uint`	`unsigned int`
`c_ll`	`long long`
`c_ull`	`unsigned long long`
`c_l`	`long`
`c_ul`	`unsigned long`
`c_size_t`	`size_t`
`c_ssize_t`	`ssize_t`
`c_schar`	`signed char`
`c_uchar`	`unsigned char`
`c_short`	`short`
`c_ushort`	`unsigned short`
`c_bool`	`_Bool`
`c_float`	`float`
`c_double`	`double`
`c_ldouble`	`long double`
`c_intptr_t`	`intptr_t`
`c_uintptr_t`	`uintptr_t`
`c_ptrdiff_t`	`ptrdiff_t`
`c_intmax_t`	`intmax_t`
`c_uintmax_t`	`uintmax_t`
`c_wchar_t`	`wchar_t`

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