Linux, qsort, array, pointer, question.

[CNewbie]

I am very new to C and C+, and I am trying to teach myself from VERY outdated text books, and I can't seem to figure this out.
No matter what I do, the code below will either not compile with errors, or compile and then seg-fault when it hits the qsort function.
I have tried all changing the symbols around, but without good C programing skills, I'm grasping at straws.

I just want this to compile and not seg fault.
If someone could look it over, and maybe tell me where and why its having a problem. Maybe a breif explaination of how to copy a pointer to a 2-d array, and vice-versa.
Oh yea, I use GCC and Linux. This example may be off a * or & here and there. I think.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>

char tstring[256];
char tgot[256];
char tname[256];
char *tdata[500][256];
int tfi=0;
int i=0;
DIR *pd;
FILE *pFile;
struct dirent *allp;
static int scomp(const void *, const void *);
int main(){
pd = opendir (&quot;/mp3s&quot;
if ( pd != NULL ) {
while ( (allp = readdir(pd)) ) {
sprintf(tstring,&quot;%s&quot;,allp->d_name);
strcpy(tgot,tstring);
strcpy(tname,(&tgot[0]));
sprintf(*tdata[tfi],&quot;%s&quot;,&tname);
tfi++;
}
}
tfi=tfi-1;
closedir(pd);
qsort(tdata, tfi, sizeof tdata[0], scomp);
pFile = fopen (&quot;List.m3u&quot;,&quot;wt&quot;
do {
fputs(tdata[ti],pFile);
puts(tdata);
i++;
}while (i<=tfi)
fclose (pFile);
return 0;
}


static int scomp(const void *p1, const void *p2){
char *a = * (char **) p1;
char *b = * (char **) p2;
return strcasecmp(a,b);
}

ANY help would be great.

 

[Guest_imported]

I have not played with qsort for a couple years, but I seem to recall that it takes a pointer to a function that does the comparison. It looks like scomp is your comparison function, but I don't see where you declare and initilaize a pointer to it. I think it needs something like:
char *comparison
comparison=&scomp

Ofcourse I'm so rusty with the syntax that I'm probably embarrassing myself!

<< If I don't pay my property taxes, they'll take my property. If I don't pay my syntax, will they take away my sins? >>

 

[ifincham]

Hi,

Mine's a bit rusty too unfortunately... Have a look at this example code which might help -->

http://heather.cs.ucdavis.edu/~matloff/UnixAndC/CLanguage/CLibQSort.html

.

Regards