• glen (11/11) Apr 20 2006 Hi All,
• Derek Parnell (45/60) Apr 20 2006 On the assumption that 'char**' points to an array of 'char*' and that
• BCS (11/22) Apr 21 2006 this is quick and dirty but should work
• Daniel Keep (13/17) Apr 21 2006 Read it right-to-left.

glen <glen_member pathlink.com> writes:

Hi All,
This seemingly simple thing is causing me alot of trouble.  Can someone show me
how I can convert an array of char[][] to a char**.  

Here is the pseudo code...

void runWithArgs( char[][] args ) {
char** execArgs;

// convert args to execArgs

execv( toStringz( "myprog" ), execArgs );

}


thanks,
Glen

Derek Parnell <derek psych.ward> writes:

On Fri, 21 Apr 2006 02:07:17 +0000 (UTC), glen wrote:

 Hi All,
 This seemingly simple thing is causing me alot of trouble.  Can someone show me
 how I can convert an array of char[][] to a char**.  
 
 Here is the pseudo code...
 
 void runWithArgs( char[][] args ) {
 char** execArgs;
 
 // convert args to execArgs
 
 execv( toStringz( "myprog" ), execArgs );
 
 }
 

On the assumption that 'char**' points to an array of 'char*' and that
array is terminated with a null pointer, then this might be what you are
looking for ...

-----------------
import std.string;
char** toArgList(char[][] pOrig)
{
    char*[] lTemp;
    lTemp.length = pOrig.length + 1;
    foreach(int i, char[] pc; pOrig)
    {
        lTemp[i] = toStringz(pc);
    }
    lTemp[$-1] = null;

    return lTemp.ptr;
}

void main(char[][] pArgs)
{
    char** lOldStyle;

    lOldStyle = toArgList(pArgs);

    // Use the counted method of accessing them.
    for(int i = 0; i < pArgs.length; i++)
    {
        printf("%d '%s'\n", i, *(lOldStyle+i));
    }

    // Use the terminating null method of accessing them.
    int j;
    char* cp;
    while(true)
    {
        cp = *(lOldStyle+j);
        if (cp == null)
            break;
        printf("%d '%s'\n", j, cp);
        j++;
    }

}
-----------------

-- 
Derek
(skype: derek.j.parnell)
Melbourne, Australia
"Down with mediocracy!"
21/04/2006 1:07:07 PM

BCS <BCS_member pathlink.com> writes:

In article <e29eol$5sa$1 digitaldaemon.com>, glen says...
Hi All,
This seemingly simple thing is causing me alot of trouble.  Can someone show me
how I can convert an array of char[][] to a char**.  

Here is the pseudo code...

void runWithArgs( char[][] args ) {
char** execArgs;

// convert args to execArgs

execv( toStringz( "myprog" ), execArgs );

}


thanks,
Glen

this is quick and dirty but should work

char[][] src; // what to convert

alias char* cahr_p;   
// alias b/c I can't remember the syntax for a array of ptrs

char_p[] res = new char_p[src.length+1];

foreach(int i, char[] st, src)
res[i] = st.ptr;

res[$-1] = null;

// now use

res.ptr

Daniel Keep <daniel.keep.lists gmail.com> writes:

[snip]
 
 alias char* cahr_p;   
 // alias b/c I can't remember the syntax for a array of ptrs
 

Read it right-to-left.

char*[] <-- array of pointers to chars

If that doesn't help, you can always make an alias, and *then* expand it.

alias char* char_p;

char_p[]
    --> (char*)[]
    -->   char*[]

At least, that's how I work it out :)

	-- Daniel

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