Index: config/gen/platform/generic/exec.c
===================================================================
--- config/gen/platform/generic/exec.c	(版本 42299)
+++ config/gen/platform/generic/exec.c	(工作副本)
@@ -55,11 +55,11 @@
     }
     else {
         /* child */
-        char *cmd    = Parrot_str_to_cstring(interp, command);
-        int   status = execlp("sh", "sh", "-c", cmd, (void *)NULL);
+        char * const cmd    = Parrot_str_to_cstring(interp, command);
+        int          status = execlp("sh", "sh", "-c", cmd, (void *)NULL);
 
         /* if we get here, something's horribly wrong, but free anyway... */
-        mem_sys_free(cmd);
+        Parrot_str_free_cstring(cmd);
 
         if (status)
             exit(status);
@@ -97,8 +97,7 @@
     if (child) {
         /* parent */
         int status;
-        pid_t returnstat;
-        returnstat = waitpid(child, &status, 0);
+        pid_t returnstat = waitpid(child, &status, 0);
         UNUSED(returnstat);
         return status;
     }
@@ -106,17 +105,16 @@
         /* child. Be horribly profligate with memory, since we're
            about to be something else */
         int status, i;
-        char **argv;
         STRING *s;
-        char *cmd;
+        char   *cmd;
+        char  **argv = (char **)mem_sys_allocate((len+1)*sizeof (char *));
 
-        argv = (char **)mem_sys_allocate((len+1)*sizeof (char *));
         for (i = 0; i < len; ++i) {
             s = VTABLE_get_string_keyed_int(interp, cmdargs, i);
             argv[i] = Parrot_str_to_cstring(interp, s);
         }
+
         cmd = argv[0];
-        argv[i] = NULL;
 
         status = execvp(cmd, argv);
         /* if we get here, something's horribly wrong... */
@@ -140,8 +138,8 @@
 {
     /* Be horribly profligate with memory, since we're
        about to be something else */
-    char *cmd  = Parrot_str_to_cstring(interp, command);
-    int status = execlp("sh", "sh", "-c", cmd, (void *)NULL);
+    char * const cmd    = Parrot_str_to_cstring(interp, command);
+    int          status = execlp("sh", "sh", "-c", cmd, (void *)NULL);
 
     /* if we get here, something's horribly wrong... */
     if (status)
Index: config/gen/platform/win32/exec.c
===================================================================
--- config/gen/platform/win32/exec.c	(版本 42300)
+++ config/gen/platform/win32/exec.c	(工作副本)
@@ -41,10 +41,10 @@
     DWORD status = 0;
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
-    int free_it = 0;
-    char* cmd = (char *)mem_sys_allocate(command->strlen + 4);
-    char* shell = Parrot_getenv(interp, Parrot_str_new(interp, "ComSpec", strlen("ComSpec")));
-    char* cmdin = Parrot_str_to_cstring(interp, command);
+    int         free_it = 0;
+    char*       cmd     = (char *)mem_sys_allocate(command->strlen + 4);
+    char*       shell   = Parrot_getenv(interp, Parrot_str_new(interp, "ComSpec", strlen("ComSpec")));
+    char* const cmdin   = Parrot_str_to_cstring(interp, command);
 
     strcpy(cmd, "/c ");
     strcat(cmd, cmdin);
@@ -95,11 +95,10 @@
     DWORD status = 0;
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
-    int pmclen;
-    int cmdlinelen = 1000;
-    int cmdlinepos = 0;
-    char *cmdline = (char *)mem_sys_allocate(cmdlinelen);
-    int i;
+    int   pmclen, i;
+    int   cmdlinelen = 1000;
+    int   cmdlinepos = 0;
+    char *cmdline    = (char *)mem_sys_allocate(cmdlinelen);
 
     /* Ensure there's something in the PMC array. */
     pmclen = VTABLE_elements(interp, cmdargs);
@@ -109,8 +108,8 @@
 
     /* Now build command line. */
     for (i = 0; i < pmclen; i++) {
-        STRING *s = VTABLE_get_string_keyed_int(interp, cmdargs, i);
-        char *cs  = Parrot_str_to_cstring(interp, s);
+        STRING      *s  = VTABLE_get_string_keyed_int(interp, cmdargs, i);
+        char * const cs = Parrot_str_to_cstring(interp, s);
         if (cmdlinepos + (int)s->strlen + 3 > cmdlinelen) {
             cmdlinelen += s->strlen + 4;
             cmdline = (char *)mem_sys_realloc(cmdline, cmdlinelen);
@@ -162,8 +161,8 @@
 Parrot_Exec_OS_Command(PARROT_INTERP, STRING *command)
 {
     int status;
-    char *in = Parrot_str_to_cstring(interp, command);
-    char *cmd = NULL;
+    char * const in   = Parrot_str_to_cstring(interp, command);
+    char *       cmd  = NULL;
     const char **argv = (const char **)mem_sys_allocate_zeroed(2 * sizeof (int));
 
     /* Grab string, extract command and parameters. */
@@ -223,6 +222,8 @@
         curPos ++;
     }
 
+    Parrot_str_free_cstring(in);
+
     /* If we still have a seek char, then the input was improper. */
     if (seekChar)
         Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_NOSPAWN,
Index: src/debug.c
===================================================================
--- src/debug.c	(版本 42299)
+++ src/debug.c	(工作副本)
@@ -1277,7 +1277,7 @@
             tmp_stdin, readline,
             "S->S", prompt, & s);
         {
-        char * aux = Parrot_str_to_cstring(interpdeb, s);
+        char * const aux = Parrot_str_to_cstring(interpdeb, s);
         strcpy(c, aux);
         Parrot_str_free_cstring(aux);
         }
Index: src/dynext.c
===================================================================
--- src/dynext.c	(版本 42299)
+++ src/dynext.c	(工作副本)
@@ -233,8 +233,8 @@
 {
     ASSERT_ARGS(dlopen_string)
 
-    char *pathstr = Parrot_str_to_cstring(interp, path);
-    void *handle = Parrot_dlopen(pathstr);
+    char * const pathstr = Parrot_str_to_cstring(interp, path);
+    void *       handle  = Parrot_dlopen(pathstr);
     Parrot_str_free_cstring(pathstr);
     return handle;
 }
Index: src/interp/inter_misc.c
===================================================================
--- src/interp/inter_misc.c	(版本 42299)
+++ src/interp/inter_misc.c	(工作副本)
@@ -341,9 +341,9 @@
 
             else {
                 /* Need to strip back to what follows the final / or \. */
-                STRING *fullname   = VTABLE_get_string(interp, exe_name);
-                char   *fullname_c = Parrot_str_to_cstring(interp, fullname);
-                int     pos        = strlen(fullname_c) - 1;
+                STRING *       fullname   = VTABLE_get_string(interp, exe_name);
+                char   * const fullname_c = Parrot_str_to_cstring(interp, fullname);
+                int            pos        = strlen(fullname_c) - 1;
 
                 while (pos              >  0
                 &&     fullname_c[pos] != '/'
@@ -354,7 +354,7 @@
                     pos++;
 
                 basename = Parrot_str_new(interp, fullname_c + pos, 0);
-                mem_sys_free(fullname_c);
+                Parrot_str_free_cstring(fullname_c);
 
                 return basename;
             }
Index: src/io/socket_win32.c
===================================================================
--- src/io/socket_win32.c	(版本 42299)
+++ src/io/socket_win32.c	(工作副本)
@@ -443,10 +443,8 @@
 Parrot_io_sockaddr_in(PARROT_INTERP, ARGIN(STRING *addr), INTVAL port)
 {
     ASSERT_ARGS(Parrot_io_sockaddr_in)
-    PMC * sockaddr;
-    char * s;
-
-    s = Parrot_str_to_cstring(interp, addr);
+    PMC  * sockaddr;
+    char * const s = Parrot_str_to_cstring(interp, addr);
     sockaddr = pmc_new(interp, enum_class_Sockaddr);
     get_sockaddr_in(interp, sockaddr, s, port);
     Parrot_str_free_cstring(s);
Index: src/io/unix.c
===================================================================
--- src/io/unix.c	(版本 42299)
+++ src/io/unix.c	(工作副本)
@@ -756,7 +756,7 @@
     }
 
 #  else
-    UNUSED(l);
+    UNUSED(filehandle);
     UNUSED(command);
     UNUSED(flags);
     Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_UNIMPLEMENTED,
Index: src/io/win32.c
===================================================================
--- src/io/win32.c	(版本 42299)
+++ src/io/win32.c	(工作副本)
@@ -693,8 +693,6 @@
             NULL, NULL, TRUE, 0,
             NULL, NULL, &start, &procinfo) == 0)
         goto fail;
-    Parrot_str_free_cstring(cmd);
-    cmd = NULL;
     if (f_read) {
         Parrot_io_set_os_handle(interp, io, hread);
         CloseHandle(hwrite);
@@ -703,6 +701,8 @@
         Parrot_io_set_os_handle(interp, io, hwrite);
         CloseHandle(hread);
     }
+
+    Parrot_str_free_cstring(cmd); 
     CloseHandle(procinfo.hThread);
     VTABLE_set_integer_keyed_int(interp, io, 0, (INTVAL)procinfo.hProcess);
     return io;
Index: src/pmc/codestring.pmc
===================================================================
--- src/pmc/codestring.pmc	(版本 42299)
+++ src/pmc/codestring.pmc	(工作副本)
@@ -278,14 +278,16 @@
 
   METHOD charname_to_ord(STRING *name) {
 #if PARROT_HAS_ICU
-    UChar32    codepoint;
-    UErrorCode err       = U_ZERO_ERROR;
-    char       *cstr     = Parrot_str_to_cstring(INTERP, name);
-    codepoint = u_charFromName(U_EXTENDED_CHAR_NAME, cstr, &err);
+    UErrorCode         err       = U_ZERO_ERROR;
+    char       * const cstr      = Parrot_str_to_cstring(INTERP, name);
+    UChar32            codepoint = u_charFromName(U_EXTENDED_CHAR_NAME, cstr, &err);
+
     Parrot_str_free_cstring(cstr);
+
     if (U_SUCCESS(err)) {
         RETURN(INTVAL codepoint);
     }
+
     RETURN(INTVAL -1);
 #else
     Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_LIBRARY_ERROR,
Index: src/pmc/os.pmc
===================================================================
--- src/pmc/os.pmc	(版本 42299)
+++ src/pmc/os.pmc	(工作副本)
@@ -476,11 +476,11 @@
 */
     METHOD readdir(STRING *path) {
 #ifndef _MSC_VER
+        char  * const cpath = Parrot_str_to_cstring(interp, path);
+        DIR           *dir  = opendir(cpath);
         struct dirent *dirent;
         PMC           *array;
-        char          *cpath = Parrot_str_to_cstring(interp, path);
         STRING        *retval;
-        DIR           *dir   = opendir(cpath);
 
         Parrot_str_free_cstring(cpath);
 
Index: src/pmc/string.pmc
===================================================================
--- src/pmc/string.pmc	(版本 42299)
+++ src/pmc/string.pmc	(工作副本)
@@ -202,8 +202,8 @@
 
         /* Only allow constant PMCs to embed constant strings */
         if (PObj_constant_TEST(SELF) && !PObj_constant_TEST(value)) {
-            char *copy = Parrot_str_to_cstring(INTERP, value);
-            value      = Parrot_str_new_init(INTERP, copy, strlen(copy),
+            char * const copy = Parrot_str_to_cstring(INTERP, value);
+            value             = Parrot_str_new_init(INTERP, copy, strlen(copy),
                 PARROT_DEFAULT_ENCODING, PARROT_DEFAULT_CHARSET,
                 PObj_constant_FLAG);
             Parrot_str_free_cstring(copy);