Dynamically create an array of strings with malloc

You should assign an array of char pointers, and then, for each pointer assign enough memory for the string:

char **orderedIds;orderedIds = malloc(variableNumberOfElements * sizeof(char*));for (int i = 0; i < variableNumberOfElements; i++)    orderedIds[i] = malloc((ID_LEN+1) * sizeof(char)); // yeah, I know sizeof(char) is 1, but to make it clear...

Seems like a good way to me. Although you perform many mallocs, you clearly assign memory for a specific string, and you can free one block of memory without freeing the whole "string array"

char **orderIds;orderIds = malloc(variableNumberOfElements * sizeof(char*));for(int i = 0; i < variableNumberOfElements; i++) {  orderIds[i] = malloc((ID_LEN + 1) * sizeof(char));  strcpy(orderIds[i], your_string[i]);}

Given that your strings are all fixed-length (presumably at compile-time?), you can do the following:

char (*orderedIds)[ID_LEN+1]    = malloc(variableNumberOfElements * sizeof(*orderedIds));// Clear-upfree(orderedIds);

A more cumbersome, but more general, solution, is to assign an array of pointers, and psuedo-initialising them to point at elements of a raw backing array:

char *raw = malloc(variableNumberOfElements * (ID_LEN + 1));char **orderedIds = malloc(sizeof(*orderedIds) * variableNumberOfElements);// Set each pointer to the start of its corresponding section of the raw buffer.for (i = 0; i < variableNumberOfElements; i++){    orderedIds[i] = &raw[i * (ID_LEN+1)];}...// Clear-up pointer arrayfree(orderedIds);// Clear-up raw arrayfree(raw);