On Sat, 2 May 2015, Alfred wrote:
Hello to all.
While working on fpcup, I did encounter the following problem.
Fpcup has modules that implement automatic download and install of packages.
One of these modules is indy.
Indy has a svn server that needs a username. No password is needed.
However, if a username is given to a command line svn client, this svn-client
wants to have a password too.
This password has to be empty.
Fpcup uses TProcess to execute commands.
But it seems that TProcess cannot handle empty parameters correctly (on
Linux).
That is debatable:
The question is: how does a C program interpret a Nil argv[] pointer ?
Because a Nil pointer is added to the Argv[] array, so the argument is there.
It processes the parameters, including the empty password, by generating a
list of (p)pchar strings.
It uses strnew to accomplish this.
But strnew returns nil for an empty string (Delphi does not return nil in
this case).
Do you have a test for this ?
My question:
Is this expected behavior of TProcess ?
Or should TProcess be changed.
Or strnew (and strpas) ?
Thanks.
Additional info
Sourcefile : process.inc, inside fpc\packages\fcl-process\src\unix :
Function StringsToPCharList(List : TStrings) : PPChar;
Var
I : Integer;
S : String;
begin
I:=(List.Count)+1;
GetMem(Result,I*sizeOf(PChar));
PPCharArray(Result)^[List.Count]:=Nil;
For I:=0 to List.Count-1 do
begin
S:=List[i];
Result[i]:=StrNew(PChar(S)); <--------------------------- here
Pchar(S) will return a pointer to an empty string (essentially, a pointer to a
#0 char)
if S is empty. That means that StrNew would need to be adapted.
However, for backwards compatibility with FPC, it may be better to simply change
TProcess to add a pointer to a zero character #0
Michael.
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