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How to initialise an element of array to NULL.For example if I have char *array[10]; I want last element to be NULL, so that I can pass this array to execv
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Array elements are initialized to 0 if they are a numeric type ( int or double ), false if they are of type boolean , or null if they are an object type like String .
You can't initialise a char array with NULL , arrays can never be NULL . You seem to be mixing up pointers and arrays. A pointer could be initialised with NULL . char str[5] = {0};
The array will be initialized to 0 in case we provide empty initializer list or just specify 0 in the initializer list. Designated Initializer: This initializer is used when we want to initialize a range with the same value. This is used only with GCC compilers.
If you have a char[] , you can zero-out individual elements using this: char arr[10] = "foo"; arr[1] = '\0'; Note that this isn't the same as assigning NULL , since arr[1] is a char and not a pointer, you can't assign NULL to it.
To initialise an array of char* to all NULLs:
char* array[10] = { NULL }; /* The remaining elements are implicitly NULL. */
If you want to provide initial elements for execv():
char* array[10] = { "/usr/bin/ls", "-l" }; /* Again, remaining elements NULL. */
or if you wish to omit the dimension from the array declaration:
char* array[] = { "/usr/bin/ls", "-l", NULL };
NULL is nothing but : #define NULL (void*) 0 UL
The NULL you are talking about is nul character which is '\0'
see man execv page or other exec processes .. it's actually take variable number of arguments
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