Clarion data type equivalents

Most of the C types are from Carl Barnes' excellent Clarion Magazine article Compiling C with the Clarion IDE, Part 1: It's Easier Than You Think.

C type	Clarion type
*	pass by address - <omittable>
&	pass by address - required
[#]	Array, use `DIM(#)`. The name of an array is actually a pointer to the first element of the array. So arrays tend to be passed by address even though you do not see an asterisk.
`char, unsigned char, signed char`	`BYTE`, but probably a string type
`char *, char[]`	`CSTRING` or `STRING` (need `RAW`). If the array has a dimension number it tends to be a fixed length string e.g. `char Digest[16]` is a `STRING(16)`. A `char ` could be a `BYTE`, but it is rare.
char **	This is a pointer to a pointer. There's an example of this in John Taylor's ClarionMag article Embedding The SQLite Engine In Clarion Applications. The C parameter is `char **errmsg` and the Clarion parameter is a `Long`. You need to declare two variables, a CString reference and a Long: `CStringRef &CString` `CStringRefAddress Long` You pass in the CStringRefAddress variable to the function call. If it comes back as a non-zero value, you obtain the string this way: `CStringRef &= (CStringRefAddress)` If the pointer is to a string array you use a similar technique. From John Christ: The value returned by the function is a pointer to the 1st (or in C, 0th) element of an array of pointers to strings. You dereference the pointer to to the first element and that is a pointer to the first string. You add 4 (in 32 bit code, 8 in 64 bit code which doesn't yet exist in the Clarion world) to the original pointer and you are now pointing to the second pointer. Add 4 again, the third pointer, and so on. When the derefenced pointer is zero, you've reached the end of the array.
`struct`	`GROUP` (need `RAW`)
`unsigned short`	`USHORT`
`signed short, short`	`SHORT`
`int, signed int,` `long, signed long,` `signed`	`SIGNED` or `LONG -` `UNSIGNED` is `Equate(Long)`
`unsigned, unsigned long, unsigned int`	`ULONG` - avoid using the `ULONG` type in Clarion. The object code created for `ULONG` math uses the decimal library, which is much slower than the code used for a `LONG`. The `UNSIGNED` type is equated to a `LONG`, which is preferable.
`float`	`SREAL`
`double`	`REAL`
`void`	Usually appears as a return type, indicating that nothing is returned.
`void *`	This is a pointer to something. Use a `LONG` or `UNSIGNED`.