pdfRemoveFormFieldChoiceSub

int32_t __stdcall pdfRemoveFormFieldChoiceSubA(PPDF IPDF, int32_t Index, const char* SubName);
int32_t __stdcall pdfRemoveFormFieldChoiceSubW(PPDF IPDF, int32_t Index, const wchar_t* SubName);

function pdfRemoveFormFieldChoiceSubA(const IPDF: PPDF; Index: Integer; SubName: PAnsiChar): Integer; stdcall;
function pdfRemoveFormFieldChoiceSubW(const IPDF: PPDF; Index: Integer; SubName: PWideChar): Integer; stdcall;

Purpose. Remove a Choice-field /Opt entry by its export-value name (SubName) — note Index here addresses the field itself (matching this SDK's frequent Index-actually-means-Handle naming, already confirmed for pdfSetAnnotIntProperty et al., Annotation Appearance and Properties), not the option position within /Opt.

Return value. Non-zero if SubName was found on that field and removed; 0 otherwise.

C# (P/Invoke)

public static extern int pdfRemoveFormFieldChoiceSubW(IntPtr IPDF, int Index, IntPtr SubName);
public static extern int pdfRemoveFormFieldChoiceSub(IntPtr IPDF, int Index, IntPtr SubName);
public static extern int pdfRemoveFormFieldChoiceSubA(IntPtr IPDF, int Index, IntPtr SubName);