Why is strtok causing a segmentation fault?

strtok modifies its first argument, hence it should be modifiable.

Maybe ReadName() returns a pointer to a read-only char array.Can you show us your ReadName() function.

If that is the reason for seg-faullt, you can create a copy of the char array before you pass it to strtok using the strdup function like:

char *copy = strdup(m);
token = strtok(copy,'-');
....
....
free(copy); // free the copy once you are done using it.

token=strtok(m,'-'); should generate a compiler warning because the second parameter of strtok() is a const char * pointing to multiple delimiters, not a single char delimiter:

char *strtok(char *str, const char *delim);

The ASCII code of '-' is 0x2D, so passing it as the second parameter of strtok() will cause strtok() to dereference the address 0x0000002D, which will cause a segfault or access violation on most modern operating systems. To fix this, use a string literal instead of a character literal: token=strtok(m,"-");

There's also the issue of how the return value of ReadName() is allocated, which others have addressed in their answers.