Forward declaration is not possible

[Peter Haase <p.haase@tu-harburg.de>]

Hi,
using GSL to implement some random generators, I would like to make a forward 
declaration for 'gsl_rng' and 'gsl_rng_type' (Otherwise, I have to include 
the GSL header files in my header file and clients using my random generators 
must have these GSL header files available ). Unfortunatley a forward 
declaration is not possible since both 'gsl_rng' and 'gsl_rng_type' are not 
names of a struct but are defined by typedef as new types:

(In gsl_rng.h:)

typedef struct 
{
   char* name;
   ....
} gsl_rng;



The reason for this is obvious to avoid the keyword struct when using the name 
gsl_rng in c-code.

My suggestion is to use 'gsl_rng' as a name of the struct and as typename for 
that struct:

(Suggested new code in gsl_rng.h)

typedef struct gsl_rng      // ( ansi c ? if not use 'tag_gsl_rng' instead)
{
   char* name;
   ....
} gsl_rng; 

With that code it is possible to use the gsl as used before and it is possible 
to use a forward declaration and hence to avoid unneccessary #includes of the 
GSL header files. I'm not pretty shure if it's strict ANSI C code when using 
the same token 'gsl_rng' for both the name and the typename (my GCC 3.2 
Compiler does not complain about that). If that is not allowed in ANSI C, the 
token 'tag_gls_rng' could be used for the name of struct (see comment above).
Even that is much more convenient than dealing without a forward declaration.

Peter