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[bugs:#1145] inconsitent type of argc in A_GIMME-callback

Status: open
Group: v0.45
Labels: API devel
Created: Mon Jun 02, 2014 10:11 AM UTC by IOhannes m zmölnig
Last Updated: Mon Jun 02, 2014 10:11 AM UTC
Owner: Miller Puckette

recently, i received a bug-report for the "puredata" Debian-package,
that warned of conflicting declarations of the glist_scalar() function.

the problem seems to be, that glist_scalar() uses "int argc" for it's
A_GIMME argument in the declaration in g_canvas.c, but uses "t_int
argc" in the function definition in g_scalar.c.
now "t_int" is defined as a "pointer-sized integer", which is a "long
int" on amd64, thus incompatible with the 32bit "int".

it is often tempting to use "t_int" whenever possible, as it is the
Pd-native integer type.
unfortunately this can (and will) break binary compatibility in some
cases.

i think it should be well documented which types to use.
e.g. the only way to find out how to use A_GIMME is reading the source
code (where we have at least 4 occurences that use "t_int"
(glist_scalar(), curve_new(), plot_new() and drawnumber_new()) and a
lot more (>200) uses of "int".

also t_listmethod and t_anymethod in m_imp.h seem to suggest that
"int" is the correct type (though "m_imp.h" was historically
considered a "private" header, not meant for documentation).

i think it's necessary to fix all uses of "t_int argc" to "int argc".

additionally i think it would be good to:
- clearly document the function-signature for (A_GIMME) callbacks (and
while doing so, move the various callback-typedefs from m_imp.h to m_pd.h)

• split the generic "t_int" type into multiple names, that suggest
  their usage.
  afaict, the original use of "t_int" is for the dsp process function
  (t_perfroutine) , though the name does not suggest anything like this.
  probably we should move to a new (probably even more pointer-like) type
  typedef t_perfarg void*;
  and replace all other uses of t_int (e.g. the return value of
  "atom_getint()" or the struct-member "t_resample.upsample") by other
  types, e.g. "int",
  for compatibility reasons, we might need to keep the two (or more)
  types the same size, but they should be separated on a semantic level.

i'm attaching a patch that changes the use of t_int to int in A_GIMME callbacks.

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