UVM中有需要从cmmand line 输入参数的需求，所有uvm_svcmd_dpi.svh和uvm_svcmd_dpi.cc 文件就是实现功能。

uvm_svcmd_dpi.svh的源代码如下，我们可以看SV采用import的方式导入C代码函数，所有者写函数的实现在uvm_svcmd_dpi.cc 中。当定义了UVM_CMDLINE_NO_DPI的宏时，所有函数返回值要么是NULL，要么是“？”。

// Import DPI functions used by the interface to generate the// lists.`ifndef UVM_CMDLINE_NO_DPIimport "DPI-C" function string uvm_dpi_get_next_arg_c (int init);import "DPI-C" function string uvm_dpi_get_tool_name_c ();import "DPI-C" function string uvm_dpi_get_tool_version_c ();function string uvm_dpi_get_next_arg(int init=0);  return uvm_dpi_get_next_arg_c(init);endfunctionfunction string uvm_dpi_get_tool_name();  return uvm_dpi_get_tool_name_c();endfunctionfunction string uvm_dpi_get_tool_version();  return uvm_dpi_get_tool_version_c();endfunctionimport "DPI-C" function chandle uvm_dpi_regcomp(string regex);import "DPI-C" function int uvm_dpi_regexec(chandle preg, string str);import "DPI-C" function void uvm_dpi_regfree(chandle preg);`elsefunction string uvm_dpi_get_next_arg(int init=0);  return "";endfunctionfunction string uvm_dpi_get_tool_name();  return "?";endfunctionfunction string uvm_dpi_get_tool_version();  return "?";endfunctionfunction chandle uvm_dpi_regcomp(string regex); return null; endfunctionfunction int uvm_dpi_regexec(chandle preg, string str); return 0; endfunctionfunction void uvm_dpi_regfree(chandle preg); endfunction`endif

看完了uvm_svcmd_dpi.svh的源代码，让我们再看看uvm_svcmd_dpi.cc的源代码，这里面的函数是采用vpi方式实现的。

#include "uvm_dpi.h"#include 
      
       #define ARGV_STACK_PTR_SIZE 32// the total number of arguments (minus the -f/-F minus associated filenames) int argc_total;// the ptr to the array of ptrs to the argschar** argv_stack=NULL;char ** argv_ptr=NULL;void push_data(int lvl,char *entry, int cmd) {  if(cmd==0)    argc_total++;  else    *argv_ptr++=entry;}// walk one level (potentially recursive)void walk_level(int lvl, int argc, char**argv,int cmd) {    int idx;    for(idx=0; ((lvl==0) && idx
       
        0) && (*argv));idx++,argv++) {      if(strcmp(*argv, "-f") && strcmp(*argv, "-F")) {    push_data(lvl,*argv,cmd);          } else {    argv++;    idx++;    char **n=(char**) *argv;    walk_level(lvl+1,argc,++n,cmd);      }    }}const char *uvm_dpi_get_next_arg_c (int init) {    s_vpi_vlog_info info;    static int idx=0;    if(init==1)    {        // free if necessary        free(argv_stack);        argc_total=0;        vpi_get_vlog_info(&info);        walk_level(0,info.argc,info.argv,0);        argv_stack = (char**) malloc (sizeof(char*)*argc_total);        argv_ptr=argv_stack;        walk_level(0,info.argc,info.argv,1);            idx=0;            argv_ptr=argv_stack;    }    if(idx++>=argc_total)      return NULL;        return *argv_ptr++;}extern char* uvm_dpi_get_tool_name_c (){  s_vpi_vlog_info info;  vpi_get_vlog_info(&info);  return info.product;}extern char* uvm_dpi_get_tool_version_c (){  s_vpi_vlog_info info;  vpi_get_vlog_info(&info);  return info.version;}extern regex_t* uvm_dpi_regcomp (char* pattern){  regex_t* re = (regex_t*) malloc (sizeof(regex_t));  int status = regcomp(re, pattern, REG_NOSUB|REG_EXTENDED);  if(status)  {      const char * err_str = "uvm_dpi_regcomp : Unable to compile regex: |%s|, Element 0 is: %c";      char buffer[strlen(err_str) + strlen(pattern) + 1];      sprintf(buffer, err_str, pattern, pattern[0]);      m_uvm_report_dpi(M_UVM_ERROR,              (char*)"UVM/DPI/REGCOMP",                       &buffer[0],                       M_UVM_NONE,                       (char*) __FILE__,                       __LINE__);      regfree(re);      free (re);    return NULL;  }  return re;}extern int uvm_dpi_regexec (regex_t* re, char* str){  if(!re )  {    return 1;  }  return regexec(re, str, (size_t)0, NULL, 0);}extern void uvm_dpi_regfree (regex_t* re){  if(!re) return;  regfree(re);  free (re);}