GetProfileString

The GetProfileString function retrieves the string associated with the specified key in the given section of the WIN.INI file. This function is provided for compatibility with 16-bit Windows-based applications. Win32-based applications should store initialization information in the registry. 

DWORD GetProfileString(
  LPCTSTR lpAppName,        // address of section name
  LPCTSTR lpKeyName,        // address of key name
  LPCTSTR lpDefault,        // address of default string
  LPTSTR lpReturnedString,  // address of destination buffer
  DWORD nSize               // size of destination buffer
);

Parameters

lpAppName
Pointer to a null-terminated string that specifies the section containing the key. If this parameter is NULL, the function copies all section names in the file to the supplied buffer.
lpKeyName
Pointer to a null-terminated string containing the key name whose associated string is to be retrieved. If this parameter is NULL, the function copies all keys in the given section to the supplied buffer. Each string is followed by a null character, and the final string is followed by a second null character.
lpDefault
Pointer to a null-terminated default string. If the lpKeyName key cannot be found in the initialization file, GetProfileString copies the default string to the lpReturnedString buffer. This parameter cannot be NULL.

Avoid specifying a default string with trailing blank characters. The function inserts a null character in the lpReturnedString buffer to strip any trailing blanks.

Windows 95: Although lpDefault is declared as a constant parameter, the system strips any trailing blanks by inserting a null character into the lpDefault string before copying it to the lpReturnedString buffer.

Windows NT: The system does not modify the lpDefault string. This means that if the default string contains trailing blanks, the lpReturnedString and lpDefault strings will not match when compared using the lstrcmp function.

lpReturnedString
Pointer to a buffer that receives the character string.
nSize
Specifies the size, in characters, of the buffer pointed to by the lpReturnedString parameter.

Return Values

The return value is the number of characters copied to the buffer, not including the null-terminating character.

If neither lpAppName nor lpKeyName is NULL and the supplied destination buffer is too small to hold the requested string, the string is truncated and followed by a null character, and the return value is equal to nSize minus one.

If either lpAppName or lpKeyName is NULL and the supplied destination buffer is too small to hold all the strings, the last string is truncated and followed by two null characters. In this case, the return value is equal to nSize minus two.

Remarks

If the string associated with the lpKeyName parameter is enclosed in single or double quotation marks, the marks are discarded when the GetProfileString function returns the string.

The GetProfileString function is not case-sensitive; the strings can contain a combination of uppercase and lowercase letters.

A section in the WIN.INI file must have the following form:

[section]
key=string
.
.
.

An application can use the GetPrivateProfileString function to retrieve a string from a specified initialization file.

The lpDefault parameter must point to a valid string, even if the string is empty (that is, even if its first character is a null character).

Windows NT: Calls to profile functions may be mapped to the registry instead of to the initialization files. This mapping occurs when the initialization file and section are specified in the registry under the following keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\IniFileMapping

When the operation has been mapped, the GetProfileString function retrieves information from the registry, not from the initialization file; the change in the storage location has no effect on the function's behavior.

The Win32 profile functions (Get/WriteProfile*, Get/WritePrivateProfile*) use the following steps to locate initialization information:

  1. Look in the registry for the name of the initialization file, say MYFILE.INI, under IniFileMapping:

    HKEY_LOCAL_MACHINE\Software\Microsoft\
    Windows NT\CurrentVersion\IniFileMapping\myfile.ini

  2. Look for the section name specified by lpAppName. This will be a named value under myfile.ini, or a subkey of myfile.ini, or will not exist.
  3. If the section name specified by lpAppName is a named value under myfile.ini, then that value specifies where in the registry you will find the keys for the section.
  4. If the section name specified by lpAppName is a subkey of myfile.ini, then named values under that subkey specify where in the registry you will find the keys for the section. If the key you are looking for does not exist as a named value, then there will be an unnamed value (shown as <No Name>) that specifies the default location in the registry where you will find the key.
  5. If the section name specified by lpAppName does not exist as a named value or as a subkey under myfile.ini, then there will be an unnamed value (shown as <No Name>) under myfile.ini that specifies the default location in the registry where you will find the keys for the section.
  6. If there is no subkey for MYFILE.INI, or if there is no entry for the section name, then look for the actual MYFILE.INI on the disk and read its contents.

When looking at values in the registry that specify other registry locations, there are several prefixes that change the behavior of the .INI file mapping:

See Also

Registry Overview, Registry Functions, GetPrivateProfileString, WriteProfileString