GetEnvironmentVariableW function (processenv.h)

Retrieves the contents of the specified variable from the environment block of the calling process.

Syntax

DWORD GetEnvironmentVariableW(
  [in, optional]  LPCWSTR lpName,
  [out, optional] LPWSTR  lpBuffer,
  [in]            DWORD   nSize
);

Parameters

[in, optional] lpName

The name of the environment variable.

[out, optional] lpBuffer

A pointer to a buffer that receives the contents of the specified environment variable as a null-terminated string.

The maximum size of a user-defined environment variable is 32,767 characters. There is no technical limitation on the size of the environment block. However, there are practical limits depending on the mechanism used to access the block. For example, a batch file cannot set a variable that is longer than the maximum command line length. For more information, see Environment Variables.

[in] nSize

The size of the buffer pointed to by the lpBuffer parameter, including the null-terminating character, in characters.

Return value

If the function succeeds, the return value is the number of characters stored in the buffer pointed to by lpBuffer, not including the terminating null character.

If lpBuffer is not large enough to hold the data, the return value is the buffer size, in characters, required to hold the string and its terminating null character and the contents of lpBuffer are undefined.

If the function fails, the return value is zero. If the specified environment variable was not found in the environment block, GetLastError returns ERROR_ENVVAR_NOT_FOUND.

Remarks

This function can retrieve either a system environment variable or a user environment variable.

Examples

For an example, see Changing Environment Variables.

Requirements

See also

Environment Variables

GetEnvironmentStrings

SetEnvironmentVariable