mirror of https://github.com/exaloop/codon.git
56 lines
1.3 KiB
Markdown
56 lines
1.3 KiB
Markdown
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Calling C/C++ from Codon is quite easy with `from C import`, but Codon
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can also be called from C/C++ code. To make a Codon function externally
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visible, simply annotate it with `@export`:
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``` python
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@export
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def foo(n: int):
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for i in range(n):
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print(i * i)
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return n * n
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```
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Note that only top-level, non-generic functions can be exported. Now we
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can create a shared library containing `foo` (assuming source file
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*foo.codon*):
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``` bash
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codon build -o libfoo.so foo.codon
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```
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Now we can call `foo` from a C program:
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``` c
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#include <stdint.h>
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#include <stdio.h>
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int64_t foo(int64_t);
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int main() {
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printf("%llu\n", foo(10));
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}
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```
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Compile:
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``` bash
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gcc -o foo -L. -lfoo foo.c
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```
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Now running `./foo` should invoke `foo()` as defined in Codon, with an
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argument of `10`.
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# Converting types
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The following table shows the conversions between Codon and C/C++ types:
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| Codon | C/C++ |
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|-----------|--------------------------------------|
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| `int` | `long` or `int64_t` |
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| `float` | `double` |
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| `bool` | `bool` |
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| `byte` | `char` or `int8_t` |
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| `str` | `{int64_t, char*}` (length and data) |
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| `class` | Pointer to corresponding tuple |
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| `@tuple` | Struct of fields |
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