GetPrivateProfileString

The GetPrivateProfileString function retrieves a string from the specified section in an initialization file. This function is provided for compatibility with 16-bit Windows-based applications. Win32-based applications should store initialization information in the registry.

DWORD GetPrivateProfileString(

LPCTSTR lpAppName,	// points to section name
LPCTSTR lpKeyName,	// points to key name
LPCTSTR lpDefault,	// points to default string
LPTSTR lpReturnedString,	// points to destination buffer
DWORD nSize,	// size of destination buffer
LPCTSTR lpFileName	// points to initialization filename
);

Parameters

lpAppName

Points to a null-terminated string that specifies the section containing the key name. If this parameter is NULL, the GetPrivateProfileString function copies all section names in the file to the supplied buffer.

lpKeyName

Pointer to the null-terminated string containing the key name whose associated string is to be retrieved. If this parameter is NULL, all key names in the section specified by the lpAppName parameter are copied to the buffer specified by the lpReturnedString parameter.

lpDefault

Pointer to a null-terminated default string. If the lpKeyName key cannot be found in the initialization file, GetPrivateProfileString 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, Windows 95 strips any trailing blanks by inserting a null character into the lpDefault string before copying it to the lpReturnedString buffer.

Windows NT: Windows NT 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 the buffer that receives the retrieved string.

nSize

Specifies the size, in characters, of the buffer pointed to by the lpReturnedString parameter.

lpFileName

Pointer to a null-terminated string that names the initialization file. If this parameter does not contain a full path to the file, Windows searches for the file in the Windows directory.

Return Values

If the function succeeds, the return value is the number of characters copied to the buffer, not including the terminating null 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

The GetPrivateProfileString function searches the specified initialization file for a key that matches the name specified by the lpKeyName parameter under the section heading specified by the lpAppName parameter. If it finds the key, the function copies the corresponding string to the buffer. If the key does not exist, the function copies the default character string specified by the lpDefault parameter. A section in the initialization file must have the following form:

[section]
key=string
.
.
.

If lpAppName is NULL, GetPrivateProfileString copies all section names in the specified file to the supplied buffer. If lpKeyName is NULL, the function copies all key names in the specified section to the supplied buffer. An application can use this method to enumerate all of the sections and keys in a file. In either case, each string is followed by a null character and the final string is followed by a second null character. If the supplied destination buffer is too small to hold all the strings, the last string is truncated and followed by two null characters.

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

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

To retrieve a string from the WIN.INI file, use the GetProfileString function.

Windows NT:

Calls to private profile functions may be mapped to the registry instead of to the specified 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

This mapping is likely if an application modifies system-component initialization files, such as CONTROL.INI, SYSTEM.INI, and WINFILE.INI. In these cases, the GetPrivateProfileString 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:

! - this character forces all writes to go both to the registry and to the .INI file on disk.

# - this character causes the registry value to be set to the value in the Windows 3.1 .INI file when a new user logs in for the first time after setup.

@ - this character prevents any reads from going to the .INI file on disk if the requested data is not found in the registry.

USR: - this prefix stands for HKEY_CURRENT_USER, and the text after the prefix is relative to that key.

SYS: - this prefix stands for HKEY_LOCAL_MACHINE\SOFTWARE, and the text after the prefix is relative to that key.

See Also

GetProfileString, WritePrivateProfileString

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