Checking if your kit is complete... Looks good Writing Makefile for POSIX::SchedYield Microsoft (R) Program Maintenance Utility Version 6.00.8168.0 Copyright (C) Microsoft Corp 1988-1998. All rights reserved. cp lib/POSIX/SchedYield.pm blib\lib\POSIX\SchedYield.pm C:\cpanrun\build\5-10-0\bin\perl.exe C:\cpanrun\build\5-10-0\lib\ExtUtils\xsubpp -typemap C:\cpanrun\build\5-10-0\lib\ExtUtils\typemap SchedYield.xs > SchedYield.xsc && C:\cpanrun\build\5-10-0\bin\perl.exe -MExtUtils::Command -e mv SchedYield.xsc SchedYield.c Please specify prototyping behavior for SchedYield.xs (see perlxs manual) cl -c -nologo -GF -W3 -MD -Zi -DNDEBUG -O1 -DWIN32 -D_CONSOLE -DNO_STRICT -DHAVE_DES_FCRYPT -DUSE_SITECUSTOMIZE -DPRIVLIB_LAST_IN_INC -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX -MD -Zi -DNDEBUG -O1 -DVERSION=\"0.0.2\" -DXS_VERSION=\"0.0.2\" "-IC:\cpanrun\build\5-10-0\lib\CORE" SchedYield.c SchedYield.c SchedYield.xs(12) : warning C4013: 'sched_yield' undefined; assuming extern returning int Running Mkbootstrap for POSIX::SchedYield () C:\cpanrun\build\5-10-0\bin\perl.exe -MExtUtils::Command -e chmod 644 SchedYield.bs C:\cpanrun\build\5-10-0\bin\perl.exe -MExtUtils::Mksymlists -e "Mksymlists('NAME'=>\"POSIX::SchedYield\", 'DLBASE' => 'SchedYield', 'DL_FUNCS' => { }, 'FUNCLIST' => [], 'IMPORTS' => { }, 'DL_VARS' => []);" link -out:blib\arch\auto\POSIX\SchedYield\SchedYield.dll -dll -nologo -nodefaultlib -debug -opt:ref,icf -libpath:"C:\cpanrun\build\5-10-0\lib\CORE" -machine:x86 SchedYield.obj C:\cpanrun\build\5-10-0\lib\CORE\perl510.lib oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib netapi32.lib uuid.lib ws2_32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib msvcrt.lib -def:SchedYield.def Creating library blib\arch\auto\POSIX\SchedYield\SchedYield.lib and object blib\arch\auto\POSIX\SchedYield\SchedYield.exp SchedYield.obj : error LNK2001: unresolved external symbol _sched_yield blib\arch\auto\POSIX\SchedYield\SchedYield.dll : fatal error LNK1120: 1 unresolved externals NMAKE : fatal error U1077: 'link' : return code '0x460' Stop.