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[bug] mingw64-*-w64-win-iconv: Cannot open handle; convert to UTF-8


I'm writing because I'm encountering a strange bug in cygwin's distributed
x86_64-w64-mingw32 libraries. Specifically a problem with win-iconv.

-=System Info=-
OS(s): Windows 7 Professional, Windows 10 Professional Edition
Package(s): mingw64-{i686,x86_64}-win-iconv version: 0.0.6-2
Cygwin: Cygwin64, Setup 2.873

I first stared experiencing an issue with an SDL2 application I am developing.
I've been revamping my build toolkit to take advantage of the better mingw64
support in newer releases of Cygwin.

When I finally got my build system work with the host, build, target triplets,
I decided to try building some mingw32 binaries of the application.
Everything built fine, but for some reason the application always immediately
quit upon being ran, with the following error message:

      "Fatal Error: Out of memory aborting".

This happens even on a machine with 16GB of memory, 10GB of it being free.
The i686 build as well as the x86_64 build encounters this issue as well.

I downloaded the source code for mingw64-SDL2 and compiled it with

I narrowed down the issue to some code in in SDL_windows_main.c,
which calls SDL_iconv_string.

Stepping into that function, the following executes:
Breakpoint 2, SDL_iconv_string (tocode=0x4052bc <__dyn_tls_init_callback+684> "UTF-8",
    fromcode=0x4052ad <__dyn_tls_init_callback+669> "UCS-2-INTERNAL", inbuf=0x2e2dd2 "C", inbytesleft=116)
    at /usr/src/debug/mingw64-x86_64-SDL2-2.0.1-1/src/stdlib/SDL_iconv.c:863

863         size_t retCode = 0;
865         cd = SDL_iconv_open(tocode, fromcode);
866         if (cd == (SDL_iconv_t) - 1) {
868             if (!tocode || !*tocode) {
871             if (!fromcode || !*fromcode) {
874             cd = SDL_iconv_open(tocode, fromcode);
876         if (cd == (SDL_iconv_t) - 1) {
877             return NULL;

WinMain (hInst=0x400000, hPrev=0x0, szCmdLine=0x2e3859 "", sw=10)
    at /usr/src/debug/mingw64-x86_64-SDL2-2.0.1-1/src/main/windows/SDL_windows_main.c:164
164         if (cmdline == NULL) {
165             return OutOfMemory();

At first I thought it could be a bug with SDL, but to make sure, I created a very simple reproduction
of the issue using only the iconv libraray, and a simple main() function. This "test" fails
on every machine on which I have ran it, in both 32-bit and 64-bit builds.

#include <iconv.h>
#include <stdio.h>
#include <stdint.h>

// Check GCC
#if __GNUC__
#if __x86_64__ || __ppc64__
#define PTR_T int64_t
#define PTR_T int32_t

int main(int argc, char * args[])
    iconv_t handle = iconv_open("C", "UTF-8");

    if ((PTR_T) handle == -1)
        printf("Could not open handle to iconv");

    return 0;

I've uploaded a small repository with a Makefile that will conveniently set your $PATH
correctly and launch the .exe when you run build the target 'run'.

For your convenience in recreating the issue, I have uploaded the repository on github,
at the following URL.

git clone git://

I've never really submitted a bug report via mailing list, but please let me know if you need any
other information and I will try my best to help out any way I can! 

I'll try and get some debug information out of the iconv.dll library, but no promises. I
don't know much about text encoding, let alone unicode pages and whatnot. :)

 - Saul Beniquez

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