C++读写ini配置文件实现过程详解

[section]
key=string
   .
   .

获取integer
UINT GetPrivateProfileInt(
 LPCTSTR lpAppName, // section name
 LPCTSTR lpKeyName, // key name
 INT nDefault,    // return value if key name not found
 LPCTSTR lpFileName // initialization file name
);

注意：lpAppName和lpKeyName不区分大小写，当获得integer <0,那么返回0。lpFileName 必须是绝对路径，因相对路径是以C:\windows\

DWORD GetPrivateProfileString(
 LPCTSTR lpAppName,    // section name
 LPCTSTR lpKeyName,    // key name
 LPCTSTR lpDefault,    // default string
 LPTSTR lpReturnedString, // destination buffer
 DWORD nSize,       // size of destination buffer
 LPCTSTR lpFileName    // initialization file name
);

注意：lpAppName和lpKeyName不区分大小写，若lpAppName为NULL，lpReturnedString缓冲区内装载这个ini文件所有小节的列表，若为lpKeyName=NULL，就在lpReturnedString缓冲区内装载指定小节所有项的列表。lpFileName 必须是绝对路径，因相对路径是以C:\windows\，
返回值：复制到lpReturnedString缓冲区的字符数量，其中不包括那些NULL中止字符。如lpReturnedString缓冲区不够大，不能容下全部信息，就返回nSize-1（若lpAppName或lpKeyName为NULL，则返回nSize-2）

获取某一字段的所有keys和values
DWORD GetPrivateProfileSection(
 LPCTSTR lpAppName,    // section name
 LPTSTR lpReturnedString, // return buffer
 DWORD nSize,       // size of return buffer
 LPCTSTR lpFileName    // initialization file name
);

retrieves the names of all sections in an initialization file.
DWORD GetPrivateProfileSectionNames(
 LPTSTR lpszReturnBuffer, // return buffer
 DWORD nSize,       // size of return buffer
 LPCTSTR lpFileName    // initialization file name
);
其实就等于，GetPrivateProfileString(NULL,NULL,lpszReturnedBuffer,nSize,lpFileName)

/* test.ini "="号两边可以加空格，也可以不加
  [Font]
  name=宋体
  size= 12pt
  color = RGB(255,0,0)
  [Layout]
  [Body]
  */

  CString strCfgPath = _T("D:\\test.ini"); //注意：'\\'
  LPCTSTR lpszSection = _T("Font");
  int n = GetPrivateProfileInt(_T("FONT"), _T("size"), 9, strCfgPath);//n=12
  CString str;
  GetPrivateProfileString(lpszSection, _T("size"), _T("9pt"), str.GetBuffer(MAX_PATH), MAX_PATH, strCfgPath);
  str.ReleaseBuffer();//str="12pt"

  TCHAR buf[200] = { 0 };
  int nSize = sizeof(buf) / sizeof(buf[0]);
  GetPrivateProfileString(lpszSection, NULL, _T(""), buf, nSize, strCfgPath);
  //buf: "name\0size\0color\0\0"

  memset(buf, 0, sizeof(buf));
  GetPrivateProfileString(NULL, _T("size"), _T(""), buf, nSize, strCfgPath);//没Section，_T("size")没意义了，所以可以写NULL
  //可以是 GetPrivateProfileString(NULL, NULL, _T(""), buf, nSize, strCfgPath);
  //buf: "Font\0Layout\0Body\0\0"

  memset(buf, 0, sizeof(buf));
  GetPrivateProfileSection(lpszSection, buf, nSize, strCfgPath);
  //buf: "name=宋体\0size=12pt\0color=RGB(255,0,0)\0\0"  此时“=”两边不会有空格

  memset(buf, 0, sizeof(buf));
  GetPrivateProfileSectionNames(buf, nSize, strCfgPath);//等于GetPrivateProfileString(NULL, NULL, _T(""), buf, nSize, strCfgPath);
  //buf: "Font\0Layout\0Body\0\0"

BOOL WritePrivateProfileString(
 LPCTSTR lpAppName, // section name
 LPCTSTR lpKeyName, // key name
 LPCTSTR lpString,  // string to add
 LPCTSTR lpFileName // initialization file
);

The WritePrivateProfileSection function replaces the keys and values for the specified section in an initialization file. 

BOOL WritePrivateProfileSection(
 LPCTSTR lpAppName, // section name
 LPCTSTR lpString,  // data
 LPCTSTR lpFileName // file name
);

WritePrivateProfileString(_T("Layout"), _T("left"), _T("100"), strCfgPath);
  WritePrivateProfileString(_T("Layout"), _T("top"), _T("80"), strCfgPath);
  //删除某Section,包括[Layout]和其下所有Keys=Value
  WritePrivateProfileSection(_T("Layout"), NULL, strCfgPath);
  //删除某Section,包括[Layout]下所有Keys=Value,但不删除[Layout]
  WritePrivateProfileSection(_T("Layout"), _T(""), strCfgPath);
//而：WritePrivateProfileSection(NULL, NULL, strCfgPath);什么也不做，因Section为NULL

#include <vector>
#include <map>
using std::vector;
using std::map;
//获取ini文件的所有Section名
vector<CString> GetSectionsNames(LPCTSTR szIniFilePath)
{
  vector<CString> vRet;
  TCHAR buf[2048] = { 0 };
  long nSize = sizeof(buf) / sizeof(buf[0]);
  ::GetPrivateProfileSectionNames(buf, nSize, szIniFilePath);
  TCHAR *p, *q;
  p = q = buf;
  while (*p)//即 '\0' != *p
  {
    while (*q)
    {
      ++q;
    }
    CString str(p, q - p);
    vRet.push_back(str);
    p = q + 1;
    q = q + 1;
  }
  return vRet;
}
//获取某一个Section的所有 key=value
map<CString, CString> GetKeysValues(LPCTSTR szSection, LPCTSTR szIniFilePath)
{
  map<CString,CString> mapRet;
  TCHAR buf[2048] = { 0 };
  long nSize = sizeof(buf) / sizeof(buf[0]);
  GetPrivateProfileSection(szSection, buf, nSize, szIniFilePath);
  TCHAR* p = buf;
  TCHAR* q = buf;
  while (*p)
  {
    CString strKey, strValue;
    while(*q)
    {
      if (_T('=') == *q)
      {
        strKey = CString(p, q - p);
        p = q + 1;
      }
      ++q;
    }
    strValue = CString(p, q - p);
    mapRet.insert(std::make_pair(strKey, strValue));
    p = q + 1;
    q = q + 1;
  }
  return mapRet;
}