strtok function

[brent123]

I'm trying to parse the filenames in a directory into file name and extension. I'm using strtok to do the parsing but I keep getting an Segmentation fault. My code is below. What am I doing wrong?

Thanks,

#include <dirent.h>
#include <stdio.h>
#include <sys/stat.h>
#include <string.h>

int main(int argc, char *argv[]) {
DIR *dp;
struct dirent *dirp;
struct stat buf;
char *str1;
char *filename;


if ((dp = opendir(argv[1])) == NULL)
printf("can't open %s", argv[1]);
while ((dirp = readdir(dp)) != NULL){
filename = dirp->d_name;
str1 = strtok(filename,".");
printf("%s\n",str1);
str1 = strtok(NULL,".");}

closedir(dp);
exit(0);
}

 

[Salem]

1. Please use [code][/code] tags when posting code.

2. The first two entries returned by readdir() are usually "." and ".." (the current and parent directories). Trying to do strtok() on those immediately returns a NULL pointer, and thus your printf() blows up.

Also, I'd be wary of modifying the storage which is being managed by readdir(). Copy the filename to a temporary string of your own, then strtok() that.



--
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.

 

[brent123]

If the filename doesn't have a "." delimenter in it, will this cause a segmentation fault error.

 

[cpjust]

You should always check the return value of strtok() (or any function for that matter) to see if an error occurred.