Using errno which is actually linked with iconv.dll

iconv_errno.patch

# HG changeset patch
# Parent b57883f4cb4b0fe42b70fbf34fed933ab9bd7440

diff --git a/src/mbyte.c b/src/mbyte.c
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -4307,6 +4307,44 @@
 #  endif
 
 /*
+ * Get the address of 'funcname' which is imported by 'hInst' DLL.
+ */
+    static void *
+get_iconv_import_func(HINSTANCE hInst, const char *funcname)
+{
+    PBYTE        		pImage = (PBYTE)hInst;
+    PIMAGE_DOS_HEADER		pDOS = (PIMAGE_DOS_HEADER)hInst;
+    PIMAGE_NT_HEADERS		pPE;
+    PIMAGE_IMPORT_DESCRIPTOR	pImpDesc;
+    PIMAGE_THUNK_DATA		pIAT;	    /* Import Address Table */
+    PIMAGE_THUNK_DATA		pINT;	    /* Import Name Table */
+    PIMAGE_IMPORT_BY_NAME	pImpName;
+
+    if (pDOS->e_magic != IMAGE_DOS_SIGNATURE)
+	return NULL;
+    pPE = (PIMAGE_NT_HEADERS)(pImage + pDOS->e_lfanew);
+    if (pPE->Signature != IMAGE_NT_SIGNATURE)
+	return NULL;
+    pImpDesc = (PIMAGE_IMPORT_DESCRIPTOR)(pImage
+	    + pPE->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT]
+							    .VirtualAddress);
+    for (; pImpDesc->FirstThunk; ++pImpDesc)
+    {
+	pIAT = (PIMAGE_THUNK_DATA)(pImage + pImpDesc->FirstThunk);
+	pINT = (PIMAGE_THUNK_DATA)(pImage + pImpDesc->OriginalFirstThunk);
+	for (; pIAT->u1.Function; ++pIAT, ++pINT)
+	{
+	    if (IMAGE_SNAP_BY_ORDINAL(pINT->u1.Ordinal))
+		continue;
+	    pImpName = (PIMAGE_IMPORT_BY_NAME)(pImage + pINT->u1.AddressOfData);
+	    if (strcmp(pImpName->Name, funcname) == 0)
+		return (void*)pIAT->u1.Function;
+	}
+    }
+    return NULL;
+}
+
+/*
  * Try opening the iconv.dll and return TRUE if iconv() can be used.
  */
     int
@@ -4339,7 +4377,9 @@
     iconv_open	= (void *)GetProcAddress(hIconvDLL, "libiconv_open");
     iconv_close	= (void *)GetProcAddress(hIconvDLL, "libiconv_close");
     iconvctl	= (void *)GetProcAddress(hIconvDLL, "libiconvctl");
-    iconv_errno	= (void *)GetProcAddress(hMsvcrtDLL, "_errno");
+    iconv_errno	= get_iconv_import_func(hIconvDLL, "_errno");
+    if (iconv_errno == NULL)
+	iconv_errno = (void *)GetProcAddress(hMsvcrtDLL, "_errno");
     if (iconv == NULL || iconv_open == NULL || iconv_close == NULL
 	    || iconvctl == NULL || iconv_errno == NULL)
     {

👍 必要とされるかはわかりませんが出してみる価値はあると思います。

たしか、iconv_errno というエントリポイントがあったと思う。

たしか、iconv_errno というエントリポイントがあったと思う。

却下されたと聞きましたが。
https://twitter.com/nu774_qaac/status/278761156695449600
bug #28084: Please add a export function to provide an errno in libiconv.

まーじーでーw