execv的坑

......
char sz_cmd[]="/system/bin/su" ;                              
strcpy(sz_filepath,R"("chmod 4755 -R /data/user/0/com.anjian.my.myanjian/files/*")");
...
char *const argv_chmod[256] = { "su","-c",sz_filepath, NULL};
...
execv(sz_cmd, argv_chmod);
...

execv的第二个参数有引号，无法正常运行，去掉引号后正常。