[Rd] R data inspection under gdb?

[Martin Morgan]

Hi Kynn --

(gdb) call Rf_PrintValue(x)

'void' is I think the return value of R_PV()

Martin

Kynn Jones wrote:
> Hi, everyone.  I'm trying to debug an R-module, written in C, and I'm using
> gdb for this.
> 
> How can I print "standard" R objects from within C code?
> 
> BTW, I'm familiar with the advice to use R_PV given in Writing R Extensions,
> but it's not working for me.  E.g., I get
> 
> (gdb) p R_PV(x)
> $1 = void
> 
> and yet
> 
> (gdb) p *x
> $2 = {sxpinfo = {type = 16, obj = 0, named = 0, gp = 0, mark = 0, debug = 0,
> trace = 0, spare = 0, gcgen = 0, gccls = 1},
>   attrib = 0x608f98, gengc_next_node = 0xa82328, gengc_prev_node = 0xa822c8,
> u = {primsxp = {offset = 1}, symsxp = {
>       pname = 0x1, value = 0x146fb50, internal = 0x2000000a}, listsxp =
> {carval = 0x1, cdrval = 0x146fb50,
>       tagval = 0x2000000a}, envsxp = {frame = 0x1, enclos = 0x146fb50,
> hashtab = 0x2000000a}, closxp = {formals = 0x1,
>       body = 0x146fb50, env = 0x2000000a}, promsxp = {value = 0x1, expr =
> 0x146fb50, env = 0x2000000a}}}
> 
> which suggests to me that x is not "void" (whatever that's supposed to mean
> here).
> 
> 
> What I'd like to do is print out SEXP's the way that the R interactive
> interpreter would display them if one evaluated them on the command line,
> but to do this from within gdb, or at least via a PRINT function called
> directly within the C code.
> 
> Is this possible?
> 
> TIA!
> 
> Kynn
> 
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