nsis refresh environment during setup - nsis

Question

During my setup i install redistributables. After installing my program i want to execute the program during the setup. For that the redistributables are needed. But the environment is not refreshed during setup, so i can't start the program. Can i refresh the environtment during the setup, or reread the environment? Or read the system environment which has changed after the redistributable installation?
I need the environment changes made during the installation of the redistributables during the setup.
Thanks for your help.

Answer 1

I had your same issue, that I solved with a workaround, but I came across this solution and I would like to share with you.
This should reload environment variables during setup:
!include LogicLib.nsh
!include WinCore.nsh
!ifndef NSIS_CHAR_SIZE
!define NSIS_CHAR_SIZE 1
!define SYSTYP_PTR i
!else
!define SYSTYP_PTR p
!endif
!ifndef ERROR_MORE_DATA
!define ERROR_MORE_DATA 234
!endif
/*!ifndef KEY_READ
!define KEY_READ 0x20019
!endif*/
Function RegReadExpandStringAlloc
System::Store S
Pop $R2 ; reg value
Pop $R3 ; reg path
Pop $R4 ; reg hkey
System::Alloc 1 ; mem
StrCpy $3 0 ; size
loop:
System::Call 'SHLWAPI::SHGetValue(${SYSTYP_PTR}R4,tR3,tR2,i0,${SYSTYP_PTR}sr2,*ir3r3)i.r0' ; NOTE: Requires SHLWAPI 4.70 (IE 3.01+ / Win95OSR2+)
${If} $0 = 0
Push $2
Push $0
${Else}
System::Free $2
${If} $0 = ${ERROR_MORE_DATA}
IntOp $3 $3 + ${NSIS_CHAR_SIZE} ; Make sure there is room for SHGetValue to \0 terminate
System::Alloc $3
Goto loop
${Else}
Push $0
${EndIf}
${EndIf}
System::Store L
FunctionEnd
Function RefreshProcessEnvironmentPath
System::Store S
Push ${HKEY_CURRENT_USER}
Push "Environment"
Push "Path"
Call RegReadExpandStringAlloc
Pop $0
${IfThen} $0 <> 0 ${|} System::Call *(i0)${SYSTYP_PTR}.s ${|}
Pop $1
Push ${HKEY_LOCAL_MACHINE}
Push "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
Push "Path"
Call RegReadExpandStringAlloc
Pop $0
${IfThen} $0 <> 0 ${|} System::Call *(i0)${SYSTYP_PTR}.s ${|}
Pop $2
System::Call 'KERNEL32::lstrlen(t)(${SYSTYP_PTR}r1)i.R1'
System::Call 'KERNEL32::lstrlen(t)(${SYSTYP_PTR}r2)i.R2'
System::Call '*(&t$R2 "",&t$R1 "",i)${SYSTYP_PTR}.r0' ; The i is 4 bytes, enough for a ';' separator and a '\0' terminator (Unicode)
StrCpy $3 ""
${If} $R1 <> 0
${AndIf} $R2 <> 0
StrCpy $3 ";"
${EndIf}
System::Call 'USER32::wsprintf(${SYSTYP_PTR}r0,t"%s%s%s",${SYSTYP_PTR}r2,tr3,${SYSTYP_PTR}r1)?c'
System::Free $1
System::Free $2
System::Call 'KERNEL32::SetEnvironmentVariable(t"PATH",${SYSTYP_PTR}r0)'
System::Free $0
System::Store L
FunctionEnd
Section
Call RefreshProcessEnvironmentPath
SectionEnd
Source: http://forums.winamp.com/showpost.php?p=3028153&postcount=12