perlio.c consting

Message-ID: <20051031175411.GA18480@petdance.com>

p4raw-id: //depot/perl@25948

diff --git a/op.c b/op.c
index d1f73ea..02c1fe8 100644 (file)
--- a/op.c
+++ b/op.c
@@ -4509,7 +4509,7 @@ Perl_newATTRSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
        if (PERLDB_SUBLINE && PL_curstash != PL_debstash) {
            SV * const sv = NEWSV(0,0);
            SV * const tmpstr = sv_newmortal();
-           GV *db_postponed = gv_fetchpv("DB::postponed", GV_ADDMULTI, SVt_PVHV);
+           GV * const db_postponed = gv_fetchpv("DB::postponed", GV_ADDMULTI, SVt_PVHV);
            HV *hv;
 
            Perl_sv_setpvf(aTHX_ sv, "%s:%ld-%ld",

diff --git a/perlio.c b/perlio.c
index 23df5e8..8a23461 100644 (file)
--- a/perlio.c
+++ b/perlio.c
@@ -276,9 +276,10 @@ PerlIO_fdupopen(pTHX_ PerlIO *f, CLONE_PARAMS *param, int flags)
        const int fd = PerlLIO_dup(PerlIO_fileno(f));
        if (fd >= 0) {
            char mode[8];
-           int omode = fcntl(fd, F_GETFL);
 #ifdef DJGPP
-           omode = djgpp_get_stream_mode(f);
+           const int omode = djgpp_get_stream_mode(f);
+#else
+           const int omode = fcntl(fd, F_GETFL);
 #endif
            PerlIO_intmode2str(omode,mode,NULL);
            /* the r+ is a hack */
@@ -337,7 +338,7 @@ XS(XS_PerlIO__Layer__find)
     if (items < 2)
        Perl_croak(aTHX_ "Usage class->find(name[,load])");
     else {
-       const char *name = SvPV_nolen_const(ST(1));
+       const char * const name = SvPV_nolen_const(ST(1));
        ST(0) = (strEQ(name, "crlf")
                 || strEQ(name, "raw")) ? &PL_sv_yes : &PL_sv_undef;
        XSRETURN(1);
@@ -461,7 +462,7 @@ PerlIO_debug(const char *fmt, ...)
     dSYS;
     va_start(ap, fmt);
     if (!PL_perlio_debug_fd && !PL_tainting && PL_uid == PL_euid && PL_gid == PL_egid) {
-        const char *s = PerlEnv_getenv("PERLIO_DEBUG");
+       const char * const s = PerlEnv_getenv("PERLIO_DEBUG");
        if (s && *s)
            PL_perlio_debug_fd = PerlLIO_open3(s, O_WRONLY | O_CREAT | O_APPEND, 0666);
        else
@@ -469,21 +470,18 @@ PerlIO_debug(const char *fmt, ...)
     }
     if (PL_perlio_debug_fd > 0) {
        dTHX;
-       STRLEN len;
-       const char *s = CopFILE(PL_curcop);
 #ifdef USE_ITHREADS
+       const char * const s = CopFILE(PL_curcop);
        /* Use fixed buffer as sv_catpvf etc. needs SVs */
        char buffer[1024];
-       if (!s)
-           s = "(none)";
-       len = my_sprintf(buffer, "%.40s:%" IVdf " ", s, (IV) CopLINE(PL_curcop));
+       const STRLEN len = my_sprintf(buffer, "%.40s:%" IVdf " ", s ? s : "(none)", (IV) CopLINE(PL_curcop));
        vsprintf(buffer+len, fmt, ap);
        PerlLIO_write(PL_perlio_debug_fd, buffer, strlen(buffer));
 #else
+       const char *s = CopFILE(PL_curcop);
+       STRLEN len;
        SV * const sv = newSVpvn("", 0);
-       if (!s)
-           s = "(none)";
-       Perl_sv_catpvf(aTHX_ sv, "%s:%" IVdf " ", s,
+       Perl_sv_catpvf(aTHX_ sv, "%s:%" IVdf " ", s ? s : "(none)",
                       (IV) CopLINE(PL_curcop));
        Perl_sv_vcatpvf(aTHX_ sv, fmt, &ap);
 
@@ -554,12 +552,12 @@ PerlIO_fdupopen(pTHX_ PerlIO *f, CLONE_PARAMS *param, int flags)
 void
 PerlIO_cleantable(pTHX_ PerlIO **tablep)
 {
-    PerlIO *table = *tablep;
+    PerlIO * const table = *tablep;
     if (table) {
        int i;
        PerlIO_cleantable(aTHX_(PerlIO **) & (table[0]));
        for (i = PERLIO_TABLE_SIZE - 1; i > 0; i--) {
-           PerlIO *f = table + i;
+           PerlIO * const f = table + i;
            if (*f) {
                PerlIO_close(f);
            }
@@ -672,7 +670,7 @@ PerlIO_destruct(pTHX)
        table = (PerlIO **) (f++);
        for (i = 1; i < PERLIO_TABLE_SIZE; i++) {
            PerlIO *x = f;
-           PerlIOl *l;
+           const PerlIOl *l;
            while ((l = *x)) {
                if (l->tab->kind & PERLIO_K_DESTRUCT) {
                    PerlIO_debug("Destruct popping %s\n", l->tab->name);
@@ -691,7 +689,7 @@ PerlIO_destruct(pTHX)
 void
 PerlIO_pop(pTHX_ PerlIO *f)
 {
-    PerlIOl *l = *f;
+    const PerlIOl *l = *f;
     if (l) {
        PerlIO_debug("PerlIO_pop f=%p %s\n", (void*)f, l->tab->name);
        if (l->tab->Popped) {
@@ -717,24 +715,24 @@ PerlIO_pop(pTHX_ PerlIO *f)
 AV *
 PerlIO_get_layers(pTHX_ PerlIO *f)
 {
-     AV *av = newAV();
+    AV * const av = newAV();
 
-     if (PerlIOValid(f)) {
-         PerlIOl *l = PerlIOBase(f);
-
-         while (l) {
-              SV *name = l->tab && l->tab->name ?
-                   newSVpv(l->tab->name, 0) : &PL_sv_undef;
-              SV *arg = l->tab && l->tab->Getarg ?
-                   (*l->tab->Getarg)(aTHX_ &l, 0, 0) : &PL_sv_undef;
-              av_push(av, name);
-              av_push(av, arg);
-              av_push(av, newSViv((IV)l->flags));
-              l = l->next;
-         }
-     }
+    if (PerlIOValid(f)) {
+       PerlIOl *l = PerlIOBase(f);
+
+       while (l) {
+           SV * const name = l->tab && l->tab->name ?
+           newSVpv(l->tab->name, 0) : &PL_sv_undef;
+           SV * const arg = l->tab && l->tab->Getarg ?
+           (*l->tab->Getarg)(aTHX_ &l, 0, 0) : &PL_sv_undef;
+           av_push(av, name);
+           av_push(av, arg);
+           av_push(av, newSViv((IV)l->flags));
+           l = l->next;
+       }
+    }
 
-     return av;
+    return av;
 }
 
 /*--------------------------------------------------------------------------------------*/
@@ -792,9 +790,9 @@ static int
 perlio_mg_set(pTHX_ SV *sv, MAGIC *mg)
 {
     if (SvROK(sv)) {
-       IO *io = GvIOn((GV *) SvRV(sv));
-       PerlIO *ifp = IoIFP(io);
-       PerlIO *ofp = IoOFP(io);
+       IO * const io = GvIOn((GV *) SvRV(sv));
+       PerlIO * const ifp = IoIFP(io);
+       PerlIO * const ofp = IoOFP(io);
        Perl_warn(aTHX_ "set %" SVf " %p %p %p", sv, io, ifp, ofp);
     }
     return 0;
@@ -804,9 +802,9 @@ static int
 perlio_mg_get(pTHX_ SV *sv, MAGIC *mg)
 {
     if (SvROK(sv)) {
-       IO *io = GvIOn((GV *) SvRV(sv));
-       PerlIO *ifp = IoIFP(io);
-       PerlIO *ofp = IoOFP(io);
+       IO * const io = GvIOn((GV *) SvRV(sv));
+       PerlIO * const ifp = IoIFP(io);
+       PerlIO * const ofp = IoOFP(io);
        Perl_warn(aTHX_ "get %" SVf " %p %p %p", sv, io, ifp, ofp);
     }
     return 0;
@@ -837,8 +835,8 @@ MGVTBL perlio_vtab = {
 XS(XS_io_MODIFY_SCALAR_ATTRIBUTES)
 {
     dXSARGS;
-    SV *sv = SvRV(ST(1));
-    AV *av = newAV();
+    SV * const sv = SvRV(ST(1));
+    AV * const av = newAV();
     MAGIC *mg;
     int count = 0;
     int i;
@@ -850,8 +848,8 @@ XS(XS_io_MODIFY_SCALAR_ATTRIBUTES)
     Perl_warn(aTHX_ "attrib %" SVf, sv);
     for (i = 2; i < items; i++) {
        STRLEN len;
-       const char *name = SvPV_const(ST(i), len);
-       SV *layer = PerlIO_find_layer(aTHX_ name, len, 1);
+       const char * const name = SvPV_const(ST(i), len);
+       SV * const layer = PerlIO_find_layer(aTHX_ name, len, 1);
        if (layer) {
            av_push(av, SvREFCNT_inc(layer));
        }
@@ -1087,7 +1085,7 @@ PerlIO_list_t *
 PerlIO_default_layers(pTHX)
 {
     if (!PL_def_layerlist) {
-       const char *s = (PL_tainting) ? Nullch : PerlEnv_getenv("PERLIO");
+       const char * const s = (PL_tainting) ? Nullch : PerlEnv_getenv("PERLIO");
        PERLIO_FUNCS_DECL(*osLayer) = &PerlIO_unix;
        PL_def_layerlist = PerlIO_list_alloc(aTHX);
        PerlIO_define_layer(aTHX_ PERLIO_FUNCS_CAST(&PerlIO_unix));
@@ -1390,7 +1388,7 @@ PerlIO_context_layers(pTHX_ const char *mode)
      * Need to supply default layer info from open.pm
      */
     if (PL_curcop) {
-       SV *layers = PL_curcop->cop_io;
+       SV * const layers = PL_curcop->cop_io;
        if (layers) {
            STRLEN len;
            type = SvPV_const(layers, len);
@@ -1398,7 +1396,7 @@ PerlIO_context_layers(pTHX_ const char *mode)
                /*
                 * Skip to write part
                 */
-               const char *s = strchr(type, 0);
+               const char * const s = strchr(type, 0);
                if (s && (STRLEN)(s - type) < len) {
                    type = s + 1;
                }
@@ -1442,7 +1440,7 @@ PerlIO_resolve_layers(pTHX_ const char *layers,
     if (!PL_perlio)
        PerlIO_stdstreams(aTHX);
     if (narg) {
-       SV *arg = *args;
+       SV * const arg = *args;
        /*
         * If it is a reference but not an object see if we have a handler
         * for it
@@ -2160,7 +2158,7 @@ void
 PerlIOBase_clearerr(pTHX_ PerlIO *f)
 {
     if (PerlIOValid(f)) {
-       PerlIO *n = PerlIONext(f);
+       PerlIO * const n = PerlIONext(f);
        PerlIOBase(f)->flags &= ~(PERLIO_F_ERROR | PERLIO_F_EOF);
        if (PerlIOValid(n))
            PerlIO_clearerr(n);
@@ -2205,7 +2203,7 @@ PerlIOBase_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
            f = PerlIOBase_dup(aTHX_ f, nexto, param, flags);
     }
     if (f) {
-       PerlIO_funcs *self = PerlIOBase(o)->tab;
+       PerlIO_funcs * const self = PerlIOBase(o)->tab;
        SV *arg;
        char buf[8];
        PerlIO_debug("PerlIOBase_dup %s f=%p o=%p param=%p\n",
@@ -2430,9 +2428,7 @@ PerlIOUnix_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
     }
     new_loc = PerlLIO_lseek(fd, offset, whence);
     if (new_loc == (Off_t) - 1)
-     {
-      return -1;
-     }
+       return -1;
     PerlIOBase(f)->flags &= ~PERLIO_F_EOF;
     return  0;
 }
@@ -2488,7 +2484,7 @@ PerlIOUnix_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
 PerlIO *
 PerlIOUnix_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
 {
-    PerlIOUnix *os = PerlIOSelf(o, PerlIOUnix);
+    const PerlIOUnix * const os = PerlIOSelf(o, PerlIOUnix);
     int fd = os->fd;
     if (flags & PERLIO_DUP_FD) {
        fd = PerlLIO_dup(fd);
@@ -2745,8 +2741,8 @@ PerlIOStdio_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
 {
     char tmode[8];
     if (PerlIOValid(f)) {
-       const char *path = SvPV_nolen_const(*args);
-       PerlIOStdio *s = PerlIOSelf(f, PerlIOStdio);
+       const char * const path = SvPV_nolen_const(*args);
+       PerlIOStdio * const s = PerlIOSelf(f, PerlIOStdio);
        FILE *stdio;
        PerlIOUnix_refcnt_dec(fileno(s->stdio));
        stdio = PerlSIO_freopen(path, (mode = PerlIOStdio_mode(mode, tmode)),
@@ -2759,7 +2755,7 @@ PerlIOStdio_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
     }
     else {
        if (narg > 0) {
-           const char *path = SvPV_nolen_const(*args);
+           const char * const path = SvPV_nolen_const(*args);
            if (*mode == IoTYPE_NUMERIC) {
                mode++;
                fd = PerlLIO_open3(path, imode, perm);
@@ -2822,7 +2818,7 @@ PerlIOStdio_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
                    f = PerlIO_allocate(aTHX);
                }
                if ((f = PerlIO_push(aTHX_ f, self, mode, PerlIOArg))) {
-                   PerlIOStdio *s = PerlIOSelf(f, PerlIOStdio);
+                   PerlIOStdio * const s = PerlIOSelf(f, PerlIOStdio);
                    s->stdio = stdio;
                    PerlIOUnix_refcnt_inc(fileno(s->stdio));
                }
@@ -3556,7 +3552,7 @@ PerlIOBuf_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
 IV
 PerlIOBuf_flush(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     int code = 0;
     PerlIO *n = PerlIONext(f);
     if (PerlIOBase(f)->flags & PERLIO_F_WRBUF) {
@@ -3617,7 +3613,7 @@ PerlIOBuf_flush(pTHX_ PerlIO *f)
 IV
 PerlIOBuf_fill(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     PerlIO *n = PerlIONext(f);
     SSize_t avail;
     /*
@@ -3658,7 +3654,7 @@ PerlIOBuf_fill(pTHX_ PerlIO *f)
        }
        if (avail > 0) {
            STDCHAR *ptr = PerlIO_get_ptr(n);
-           SSize_t cnt = avail;
+           const SSize_t cnt = avail;
            if (avail > (SSize_t)b->bufsiz)
                avail = b->bufsiz;
            Copy(ptr, b->buf, avail, STDCHAR);
@@ -3684,7 +3680,7 @@ SSize_t
 PerlIOBuf_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
 {
     if (PerlIOValid(f)) {
-        const PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+        const PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
        if (!b->ptr)
            PerlIO_get_base(f);
        return PerlIOBase_read(aTHX_ f, vbuf, count);
@@ -3696,7 +3692,7 @@ SSize_t
 PerlIOBuf_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 {
     const STDCHAR *buf = (const STDCHAR *) vbuf + count;
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     SSize_t unread = 0;
     SSize_t avail;
     if (PerlIOBase(f)->flags & PERLIO_F_WRBUF)
@@ -3815,7 +3811,7 @@ PerlIOBuf_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
 Off_t
 PerlIOBuf_tell(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     /*
      * b->posn is file position where b->buf was read, or will be written
      */
@@ -3850,8 +3846,7 @@ PerlIOBuf_popped(pTHX_ PerlIO *f)
     if (b->buf && b->buf != (STDCHAR *) & b->oneword) {
        Safefree(b->buf);
     }
-    b->buf = NULL;
-    b->ptr = b->end = b->buf;
+    b->ptr = b->end = b->buf = NULL;
     PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
     return code;
 }
@@ -3864,8 +3859,7 @@ PerlIOBuf_close(pTHX_ PerlIO *f)
     if (b->buf && b->buf != (STDCHAR *) & b->oneword) {
        Safefree(b->buf);
     }
-    b->buf = NULL;
-    b->ptr = b->end = b->buf;
+    b->ptr = b->end = b->buf = NULL;
     PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
     return code;
 }
@@ -3873,7 +3867,7 @@ PerlIOBuf_close(pTHX_ PerlIO *f)
 STDCHAR *
 PerlIOBuf_get_ptr(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    const PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (!b->buf)
        PerlIO_get_base(f);
     return b->ptr;
@@ -3882,7 +3876,7 @@ PerlIOBuf_get_ptr(pTHX_ PerlIO *f)
 SSize_t
 PerlIOBuf_get_cnt(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    const PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (!b->buf)
        PerlIO_get_base(f);
     if (PerlIOBase(f)->flags & PERLIO_F_RDBUF)
@@ -3893,7 +3887,7 @@ PerlIOBuf_get_cnt(pTHX_ PerlIO *f)
 STDCHAR *
 PerlIOBuf_get_base(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (!b->buf) {
        if (!b->bufsiz)
            b->bufsiz = 4096;
@@ -3902,8 +3896,7 @@ PerlIOBuf_get_base(pTHX_ PerlIO *f)
            b->buf = (STDCHAR *) & b->oneword;
            b->bufsiz = sizeof(b->oneword);
        }
-       b->ptr = b->buf;
-       b->end = b->ptr;
+       b->end = b->ptr = b->buf;
     }
     return b->buf;
 }
@@ -3911,7 +3904,7 @@ PerlIOBuf_get_base(pTHX_ PerlIO *f)
 Size_t
 PerlIOBuf_bufsiz(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    const PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (!b->buf)
        PerlIO_get_base(f);
     return (b->end - b->buf);
@@ -3920,7 +3913,7 @@ PerlIOBuf_bufsiz(pTHX_ PerlIO *f)
 void
 PerlIOBuf_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, SSize_t cnt)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (!b->buf)
        PerlIO_get_base(f);
     b->ptr = ptr;
@@ -4009,7 +4002,7 @@ PerlIOPending_seek(pTHX_ PerlIO *f, Off_t offset, int whence)
 IV
 PerlIOPending_flush(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (b->buf && b->buf != (STDCHAR *) & b->oneword) {
        Safefree(b->buf);
        b->buf = NULL;
@@ -4033,7 +4026,7 @@ IV
 PerlIOPending_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 {
     const IV code = PerlIOBase_pushed(aTHX_ f, mode, arg, tab);
-    PerlIOl *l = PerlIOBase(f);
+    PerlIOl * const l = PerlIOBase(f);
     /*
      * Our PerlIO_fast_gets must match what we are pushed on, or sv_gets()
      * etc. get muddled when it changes mid-string when we auto-pop.
@@ -4151,7 +4144,7 @@ PerlIOCrlf_pushed(pTHX_ PerlIO *f, const char *mode, SV *arg, PerlIO_funcs *tab)
 SSize_t
 PerlIOCrlf_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 {
-    PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
+    PerlIOCrlf * const c = PerlIOSelf(f, PerlIOCrlf);
     if (c->nl) {       /* XXXX Shouldn't it be done only if b->ptr > c->nl? */
        *(c->nl) = 0xd;
        c->nl = NULL;
@@ -4173,7 +4166,7 @@ PerlIOCrlf_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
                b->posn -= b->bufsiz;
            }
            while (count > 0 && b->ptr > b->buf) {
-               int ch = *--buf;
+               const int ch = *--buf;
                if (ch == '\n') {
                    if (b->ptr - 2 >= b->buf) {
                        *--(b->ptr) = 0xa;
@@ -4203,11 +4196,11 @@ PerlIOCrlf_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 SSize_t
 PerlIOCrlf_get_cnt(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     if (!b->buf)
        PerlIO_get_base(f);
     if (PerlIOBase(f)->flags & PERLIO_F_RDBUF) {
-       PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
+       PerlIOCrlf * const c = PerlIOSelf(f, PerlIOCrlf);
        if ((PerlIOBase(f)->flags & PERLIO_F_CRLF) && (!c->nl || *c->nl == 0xd)) {
            STDCHAR *nl = (c->nl) ? c->nl : b->ptr;
          scan:
@@ -4275,8 +4268,8 @@ PerlIOCrlf_get_cnt(pTHX_ PerlIO *f)
 void
 PerlIOCrlf_set_ptrcnt(pTHX_ PerlIO *f, STDCHAR * ptr, SSize_t cnt)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
-    PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOCrlf * const c = PerlIOSelf(f, PerlIOCrlf);
     if (!b->buf)
        PerlIO_get_base(f);
     if (!ptr) {
@@ -4332,15 +4325,15 @@ PerlIOCrlf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
     if (!(PerlIOBase(f)->flags & PERLIO_F_CRLF))
        return PerlIOBuf_write(aTHX_ f, vbuf, count);
     else {
-       PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+       PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
        const STDCHAR *buf = (const STDCHAR *) vbuf;
-       const STDCHAR *ebuf = buf + count;
+       const STDCHAR * const ebuf = buf + count;
        if (!b->buf)
            PerlIO_get_base(f);
        if (!(PerlIOBase(f)->flags & PERLIO_F_CANWRITE))
            return 0;
        while (buf < ebuf) {
-           STDCHAR *eptr = b->buf + b->bufsiz;
+           const STDCHAR * const eptr = b->buf + b->bufsiz;
            PerlIOBase(f)->flags |= PERLIO_F_WRBUF;
            while (buf < ebuf && b->ptr < eptr) {
                if (*buf == '\n') {
@@ -4362,8 +4355,7 @@ PerlIOCrlf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
                    }
                }
                else {
-                   int ch = *buf++;
-                   *(b->ptr)++ = ch;
+                   *(b->ptr)++ = *buf++;
                }
                if (b->ptr >= eptr) {
                    PerlIO_flush(f);
@@ -4380,7 +4372,7 @@ PerlIOCrlf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 IV
 PerlIOCrlf_flush(pTHX_ PerlIO *f)
 {
-    PerlIOCrlf *c = PerlIOSelf(f, PerlIOCrlf);
+    PerlIOCrlf * const c = PerlIOSelf(f, PerlIOCrlf);
     if (c->nl) {
        *(c->nl) = 0xd;
        c->nl = NULL;
@@ -4458,7 +4450,7 @@ PerlIOMmap_map(pTHX_ PerlIO *f)
     if (m->len)
        abort();
     if (flags & PERLIO_F_CANREAD) {
-       PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+       PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
        const int fd = PerlIO_fileno(f);
        Stat_t st;
        code = Fstat(fd, &st);
@@ -4512,10 +4504,10 @@ PerlIOMmap_map(pTHX_ PerlIO *f)
 IV
 PerlIOMmap_unmap(pTHX_ PerlIO *f)
 {
-    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
-    PerlIOBuf *b = &m->base;
+    PerlIOMmap * const m = PerlIOSelf(f, PerlIOMmap);
     IV code = 0;
     if (m->len) {
+       PerlIOBuf * const b = &m->base;
        if (b->buf) {
            code = munmap(m->mptr, m->len);
            b->buf = NULL;
@@ -4533,8 +4525,8 @@ PerlIOMmap_unmap(pTHX_ PerlIO *f)
 STDCHAR *
 PerlIOMmap_get_base(pTHX_ PerlIO *f)
 {
-    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
-    PerlIOBuf *b = &m->base;
+    PerlIOMmap * const m = PerlIOSelf(f, PerlIOMmap);
+    PerlIOBuf * const b = &m->base;
     if (b->buf && (PerlIOBase(f)->flags & PERLIO_F_RDBUF)) {
        /*
         * Already have a readbuffer in progress
@@ -4566,8 +4558,8 @@ PerlIOMmap_get_base(pTHX_ PerlIO *f)
 SSize_t
 PerlIOMmap_unread(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 {
-    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
-    PerlIOBuf *b = &m->base;
+    PerlIOMmap * const m = PerlIOSelf(f, PerlIOMmap);
+    PerlIOBuf * const b = &m->base;
     if (PerlIOBase(f)->flags & PERLIO_F_WRBUF)
        PerlIO_flush(f);
     if (b->ptr && (b->ptr - count) >= b->buf
@@ -4624,8 +4616,8 @@ PerlIOMmap_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 IV
 PerlIOMmap_flush(pTHX_ PerlIO *f)
 {
-    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
-    PerlIOBuf *b = &m->base;
+    PerlIOMmap * const m = PerlIOSelf(f, PerlIOMmap);
+    PerlIOBuf * const b = &m->base;
     IV code = PerlIOBuf_flush(aTHX_ f);
     /*
      * Now we are "synced" at PerlIOBuf level
@@ -4652,7 +4644,7 @@ PerlIOMmap_flush(pTHX_ PerlIO *f)
 IV
 PerlIOMmap_fill(pTHX_ PerlIO *f)
 {
-    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
+    PerlIOBuf * const b = PerlIOSelf(f, PerlIOBuf);
     IV code = PerlIO_flush(f);
     if (code == 0 && !b->buf) {
        code = PerlIOMmap_map(aTHX_ f);
@@ -4666,8 +4658,8 @@ PerlIOMmap_fill(pTHX_ PerlIO *f)
 IV
 PerlIOMmap_close(pTHX_ PerlIO *f)
 {
-    PerlIOMmap *m = PerlIOSelf(f, PerlIOMmap);
-    PerlIOBuf *b = &m->base;
+    PerlIOMmap * const m = PerlIOSelf(f, PerlIOMmap);
+    PerlIOBuf * const b = &m->base;
     IV code = PerlIO_flush(f);
     if (m->bbuf) {
        b->buf = m->bbuf;
@@ -4845,8 +4837,7 @@ int
 PerlIO_puts(PerlIO *f, const char *s)
 {
     dTHX;
-    STRLEN len = strlen(s);
-    return PerlIO_write(f, s, len);
+    return PerlIO_write(f, s, strlen(s));
 }
 
 #undef PerlIO_rewind
@@ -4863,7 +4854,7 @@ int
 PerlIO_vprintf(PerlIO *f, const char *fmt, va_list ap)
 {
     dTHX;
-    SV *sv = newSVpvn("", 0);
+    SV * const sv = newSVpvn("", 0);
     const char *s;
     STRLEN len;
     SSize_t wrote;
@@ -4917,7 +4908,7 @@ PerlIO_tmpfile(void)
          f = PerlIO_fdopen(fd, "w+b");
 #else /* WIN32 */
 #    if defined(HAS_MKSTEMP) && ! defined(VMS) && ! defined(OS2)
-     SV *sv = newSVpv("/tmp/PerlIO_XXXXXX", 0);
+     SV * const sv = newSVpv("/tmp/PerlIO_XXXXXX", 0);
      /*
       * I have no idea how portable mkstemp() is ... NI-S
       */