in reply to Re: Looking at a SV in C
in thread Looking at a SV in C

The struct is self referential. The RV in the union is another pMG *. pMG = private Magic. An MG SVANY is encountered more often than a LV so thats why I based this off a MG rather than LV. Feel free to expand it. Make sure you've read Perl Illguts before and sv.h before interpreting it. Perl loves to use unions.

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Re^3: Looking at a SV in C
by BrowserUk (Patriarch) on Mar 22, 2012 at 20:07 UTC
    The struct is self referential.

    The primary purpose of the tag name on structs is to allow for self referential definitions.

    This compiles clean with MSVC:

    typedef struct pMG {
    XPVMG    *sv_any;
    U32       sv_refcnt;
    union {
        U32    sv_flags;
        struct {
            unsigned long type : 8;
            unsigned long f_IOK : 1;
            unsigned long f_NOK : 1;
            unsigned long f_POK : 1;
            unsigned long f_ROK : 1;
            unsigned long p_IOK: 1;
            unsigned long p_NOK: 1;
            unsigned long p_POK : 1;
            unsigned long p_SCREAM_phv_CLONEABLE_phv_CLONEABLE_prv_PCS
+_IMPORTED : 1;
            unsigned long s_PADSTALE_SVpad_STATE : 1;
            unsigned long s_PADTMP_SVpad_TYPED : 1;
            unsigned long s_PADMY_SVpad_OUR : 1;
            unsigned long s_TEMP : 1;
            unsigned long s_OBJECT : 1;
            unsigned long s_GMG : 1;
            unsigned long s_SMG : 1;
            unsigned long s_RMG : 1;
            unsigned long f_FAKE_SVphv_REHASH : 1;
            unsigned long f_OOK : 1;
            unsigned long f_BREAK: 1;
            unsigned long f_READONLY : 1;
            unsigned long f_AMAGIC : 1;
            unsigned long f_UTF8_SVphv_SHAREKEYS : 1;
            unsigned long pav_REAL_phv_LAZYDEL_pbm_VALID_repl_EVAL : 1
+;
            unsigned long f_IVisUV_pav_REIFY_phv_HASKFLAGS_pfm_COMPILE
+D_pbm_TAIL_prv_WEAKREF : 1;
        } flagsraw;
    };
    union {
        IV           svu_iv;
        UV           svu_uv;
        struct pMG  *svu_rv;
        char        *svu_pv;
        struct pMG **svu_array;
        HE         **svu_hash;
        GP          *svu_gp;
    } sv_u;
};

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