SetupGetStringFieldA function (setupapi.h)

Article
02/09/2023

[This function is available for use in the operating systems indicated in the Requirements section. It may be altered or unavailable in subsequent versions. SetupAPI should no longer be used for installing applications. Instead, use the Windows Installer for developing application installers. SetupAPI continues to be used for installing device drivers.]

The SetupGetStringField function retrieves a string from the specified field of a line in an INF file.

Syntax

WINSETUPAPI BOOL SetupGetStringFieldA(
  [in]      PINFCONTEXT Context,
  [in]      DWORD       FieldIndex,
  [in, out] PSTR        ReturnBuffer,
  [in]      DWORD       ReturnBufferSize,
  [out]     PDWORD      RequiredSize
);

Parameters

[in] Context

Pointer to the context for a line in an INF file.

[in] FieldIndex

The 1-based index of the field within the specified line from which the string should be retrieved. Use a FieldIndex of 0 to retrieve a string key, if present.

[in, out] ReturnBuffer

Optional pointer to a buffer that receives the null-terminated string. You should ensure the destination buffer is the same size or larger than the source buffer. This parameter can be NULL. See the Remarks section.

[in] ReturnBufferSize

Size of the buffer pointed to by ReturnBuffer, in characters. This includes the null terminator.

[out] RequiredSize

Optional pointer to a variable that receives the required size for the buffer pointed to by the ReturnBuffer parameter, in characters. If ReturnBuffer is specified and the actual size needed is larger than the value specified by ReturnBufferSize, the function fails and does not store the string in the buffer. In this case, a call to GetLastError returns ERROR_INSUFFICIENT_BUFFER. For the Unicode version of this function, the required size is in characters. This includes the null terminator.

Return value

If the function succeeds, the return value is a nonzero value.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

If this function is called with a ReturnBuffer of NULL and a ReturnBufferSize of zero, the function puts the buffer size needed to hold the specified data into the variable pointed to by RequiredSize. If the function succeeds in this, the return value is a nonzero value. Otherwise, the return value is zero and extended error information can be obtained by calling GetLastError.

You can call the function once to get the required buffer size, allocate the necessary memory, and then call the function a second time to retrieve the data. Using this technique, you can avoid errors due to an insufficient buffer size.

Note that the maximum length of any single string specified in an INF Strings section is 512 characters, including the terminating NULL. If the string length is greater than 512 it will be truncated and no error will be returned. The maximum length of any concatenated string created from one or more %strkey% tokens is 4096 characters.

Note

The setupapi.h header defines SetupGetStringField as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	setupapi.h
Library	Setupapi.lib
DLL	Setupapi.dll
API set	ext-ms-win-setupapi-inf-l1-1-1 (introduced in Windows 10, version 10.0.14393)