After not being able to use ImportC to automatically compile a C library, now I'm trying to do it myself. The library I want to use is tomlc99 which is a small C library to parse toml files. Now I compiled the library and I copied the "config.h" file and modified to make it a D file that will contain the declaration so D knows which symbols to call. I resulted with a "toml.d" file and a "main.d" file. The first one contains the decorations and the second one contains the code from the example in the usage section. However, when I try to compile, I'm getting the following error message:

main.d(51): Error: need `this` for `s` of type `char*`
Deprecation: argument `__error` for format specification `"%s"` must be `char*`, not `_error_`
main.d(57): Error: need `this` for `i` of type `long`
main.d(63): Error: need `this` for `s` of type `char*`

I uploaded the modified files so someone is able to look at them and explain me what I'm doing wrong so I can properly learn. Links:

toml.d
main.d

On Thursday, 11 November 2021 at 07:04:57 UTC, rempas wrote:

main.d(51): Error: need `this` for `s` of type `char*`
Deprecation: argument `__error` for format specification `"%s"` must be `char*`, not `_error_`
main.d(57): Error: need `this` for `i` of type `long`
main.d(63): Error: need `this` for `s` of type `char*`

Your type definition is wrong:
```D
struct toml_datum_t {
  int ok;
  union u {
    toml_timestamp_t* ts; /* ts must be freed after use */
    char*   s; /* string value. s must be freed after use */
    int     b; /* bool value */
    int64_t i; /* int value */
    double  d; /* double value */
  }
}
```

If you check the size of this struct, it's going to be 4, because `u` is a type definition. What you want is either:
```D
struct toml_datum_t {
  int ok;
  union {
    toml_timestamp_t* ts; /* ts must be freed after use */
    char*   s; /* string value. s must be freed after use */
    int     b; /* bool value */
    int64_t i; /* int value */
    double  d; /* double value */
  }
}
```

Which you access via `host.s` or:
```D
struct toml_datum_t {
  int ok;
  /// This is the type definition
  union U {
    toml_timestamp_t* ts; /* ts must be freed after use */
    char*   s; /* string value. s must be freed after use */
    int     b; /* bool value */
    int64_t i; /* int value */
    double  d; /* double value */
  }
  /// This is the field
  U u;
}
```

Note that instead of doing this work yourself, I would highly recommend the excellent dstep.

On Thursday, 11 November 2021 at 07:10:39 UTC, Mathias LANG wrote:

Your type definition is wrong:

struct toml_datum_t {
  int ok;
  union u {
    toml_timestamp_t* ts; /* ts must be freed after use */
    char*   s; /* string value. s must be freed after use */
    int     b; /* bool value */
    int64_t i; /* int value */
    double  d; /* double value */
  }
}

If you check the size of this struct, it's going to be 4,
because u is a type definition. What you want is either:

struct toml_datum_t {
  int ok;
  union {
    toml_timestamp_t* ts; /* ts must be freed after use */
    char*   s; /* string value. s must be freed after use */
    int     b; /* bool value */
    int64_t i; /* int value */
    double  d; /* double value */
  }
}

Which you access via host.s or:

struct toml_datum_t {
  int ok;
  /// This is the type definition
  union U {
    toml_timestamp_t* ts; /* ts must be freed after use */
    char*   s; /* string value. s must be freed after use */
    int     b; /* bool value */
    int64_t i; /* int value */
    double  d; /* double value */
  }
  /// This is the field
  U u;
}

Note that instead of doing this work yourself, I would highly recommend the excellent dstep.

Fixed formatting (so much for "Fix it for me").

On Thursday, 11 November 2021 at 07:15:04 UTC, Mathias LANG wrote:

Oh, now it makes sense! Thanks a lot! I will learn and use dstep in the future! Have an amazing day!