c - Segmentation fault on calling function more then once -

running function more once cause segmentation fault , cannot figure out why. im not looking alternative ways split string.

splitx continue splitting x ammount of delimiters (be '|' or '\0') , return x or number of substrings make.

i should note have restarted coding in c after 3 years of easy javascript , php missing obvious.

int splitx(char **array, char *string, int x) {     int y;     int z;     int index = 0;     int windex = 0;     for(y = 0; y < x; y++) {         z = index;         while(string[index] != '\0' && string[index] != '|') {             index++;         }         char **tempptr = realloc(array, (y+1)*sizeof(char *));         if(tempptr == null) {             free(array);             return -3;         }         array = tempptr;         array[y] = malloc(sizeof(char) * (index - z + 1));         windex = 0;         for(; z < index; z++) {             array[y][windex] = string[z];             windex++;         }         array[y][windex] = '\0';         if(string[index] == '\0')             break;         index++;     }     return y+1; }  int main() {         char **array;         int array_len = splitx(array, query, 2);         printf("%s %s %d\n", array[0], array[1], array_len);         while(array_len > 0) {             free(array[array_len-1]);             array_len--;         }         free(array);         array_len = splitx(array, "1|2\0", 2);         printf("%s %s %d\n", array[0], array[1], array_len);         while(array_len > 0) {             free(array[array_len-1]);             array_len--;         }         free(array); } 

char **array; int array_len = splitx(array, query, 2); 

this lets splitx() use uninitialized array, results in undefined behavior.

furthermore, c has no pass-by-reference - when write

 array = tempptr; 

inside function, has no visible effect outside it.

im not looking alternative ways split string.

you should be. current approach @ best non-idiomatic, has other mistakes (like returning y + 1 reason y certainly, etc.).

you reinventing wheel: string , character searching, use strstr(), strchr() , strtok_r() c standard library; duplicaitng string, use strdup() instead of going through string manually, etc., etc...

what else:

• use size_t sizes instead of int;

• maintain const correctness using const char * input strings.

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char **split(const char *s, size_t *sz) {     char **r = null;     size_t n = 0, allocsz = 0;     const char *p = s, *t = p;     int end = 0;      {         const char *tmp = strchr(p, '|');         if (tmp == null) {             p = p + strlen(p);             end = 1;         } else {             p = tmp;         }          if (++n > allocsz) {             if (allocsz == 0)                 allocsz = 4;             else                 allocsz <<= 1;              char **tmp = realloc(r, sizeof(*r) * allocsz);             if (!tmp) abort(); // or whatever, handle error             r = tmp;         }          r[n - 1] = malloc(p - t + 1);         memcpy(r[n - 1], t, p - t);         r[n - 1][p - t] = 0;          p++;         t = p;     } while (!end);      *sz = n;     return r; }