Modifying 2D char array passed to a function in C -

lacking money atm i'm offering $0.25 via paypal first person point out did wrong in code snippet -- hope doesn't violate site rules or insult anybody.

i want modify multi-dimensional array in function. gets modified while in function, when scope returns main function array unchanged.

the function headers cannot modified. helping me out.

void getalignment(char*s1, char*s2, char*s3, char*aligned[]) {     /***********************     code here assigns     char**tmp "different" "words"     ***********************/  printf("tmp in getalignment function\n"); printf("%s %s\n", tmp[0], tmp[1]); // prints "different words", expected     aligned = tmp; }  int main(void) {     // skipped code      char** aligned = (char**)malloc(sizeof(char*)*2);     aligned[0] = "should";     aligned[1] = "change";      printf("%s %s\n", aligned[0], aligned[1]); // prints "should change", expected     getalignment(s1, s2, transcript, aligned); // how change aligned during call?     printf("%s %s\n", aligned[0], aligned[1]); // prints "should change"     return 0; } 

when write inside getalignment:

aligned = (char**) malloc(2*sizeof(char*)); 

you making pointer getalignment::aligned point new memory. no longer points memory main::aligned points to. when operate on new memory, has no effect on memory main::aligned , pointing to.

(note - :: not c syntax, meaning disambiguate 2 variables both called aligned in local scope, despite fact 2 separate variables).

if intent code in getalignmentmodifies memory being pointed main::aligned remove above line.

if intent getalignment able allocate new memory, , main::aligned switched use new memory, have pass main::aligned reference (i.e. add level of indirection in function call). , don't forget free() previously-allocated memory.

btw don't cast malloc.