#include <stdio.h>
#include <unicase.h>
#include <stdlib.h>
#include <unistr.h>
#include <uninorm.h>
#include <string.h>
#include <unistr.h>
#include <unitypes.h>
void main(){
char* instring = "Hauptstraße 3"; // Works with uint8_t too
size_t length;
uint8_t *result;
size_t input_length;
input_length=strlen(instring); //u8_strlen works too
result = u8_toupper (instring, input_length, NULL, UNINORM_NFC, NULL, &length);

##</code><code>##

SV*
uppercase_utf8_2(SV* sv)
PREINIT:
    size_t len;
    char* s;
    char* upperstring; //uint8_t also
    SV* aresult;

   size_t upperlength;
CODE:
    s = SvPVbyte(sv, len);  //strings from my editor (locale?) are already utf8 encoded
    upperstring = u8_toupper (s, len, NULL, NULL,NULL, &upperlength);
    upperlength = u8_strlen(upperstring);
    aresult = newSVpv(upperstring,upperlength);
    free(upperstring);
	RETVAL = aresult;
OUTPUT:
	RETVAL

##</code><code>##

==614897== Invalid read of size 1
==614897==    at 0x484F234: strlen (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==614897==    by 0x485B74A: XS_Simple__Ngram_uppercase_utf8_2 (Ngram.xs:79)
==614897==    by 0x2441A9: ??? (in /usr/bin/perl)
==614897==    by 0x2396DD: Perl_runops_standard (in /usr/bin/perl)
==614897==    by 0x1781DA: perl_run (in /usr/bin/perl)
==614897==    by 0x14D639: main (in /usr/bin/perl)
==614897==  Address 0x5bb9282 is 0 bytes after a block of size 18 alloc'd
==614897==    at 0x484DB80: realloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==614897==    by 0x55AEF01: libunistring_u8_casemap (in /usr/lib/x86_64-linux-gnu/libunistring.so.5.0.0)
==614897==    by 0x55AF478: u8_toupper (in /usr/lib/x86_64-linux-gnu/libunistring.so.5.0.0)
==614897==    by 0x485B73F: XS_Simple__Ngram_uppercase_utf8_2 (Ngram.xs:78)
==614897==    by 0x2441A9: ??? (in /usr/bin/perl)
==614897==    by 0x2396DD: Perl_runops_standard (in /usr/bin/perl)
==614897==    by 0x1781DA: perl_run (in /usr/bin/perl)
==614897==    by 0x14D639: main (in /usr/bin/perl)
==614897== 
==614897== 
==614897== HEAP SUMMARY:
==614897==     in use at exit: 2,544,437 bytes in 9,481 blocks
==614897==   total heap usage: 33,789 allocs, 24,308 frees, 6,454,177 bytes allocated
==614897== 
==614897== 2 bytes in 1 blocks are possibly lost in loss record 1 of 1,342
==614897==    at 0x4846828: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==614897==    by 0x24EADB: Perl_sv_magicext (in /usr/bin/perl)
==614897==    by 0x24ED0A: Perl_sv_magic (in /usr/bin/perl)
==614897==    by 0x183F8C: Perl_gv_fetchpvn_flags (in /usr/bin/perl)
==614897==    by 0x174ED2: perl_parse (in /usr/bin/perl)
==614897==    by 0x14D55B: main (in /usr/bin/perl)