tvl-depot/Documentation/technical/api-argv-array.txt

66 lines
2.2 KiB
Text
Raw Normal View History

argv-array API
==============
The argv-array API allows one to dynamically build and store
NULL-terminated lists. An argv-array maintains the invariant that the
`argv` member always points to a non-NULL array, and that the array is
always NULL-terminated at the element pointed to by `argv[argc]`. This
makes the result suitable for passing to functions expecting to receive
argv from main(), or the link:api-run-command.html[run-command API].
The string-list API (documented in string-list.h) is similar, but cannot be
used for these purposes; instead of storing a straight string pointer,
it contains an item structure with a `util` field that is not compatible
with the traditional argv interface.
Each `argv_array` manages its own memory. Any strings pushed into the
array are duplicated, and all memory is freed by argv_array_clear().
Data Structures
---------------
`struct argv_array`::
A single array. This should be initialized by assignment from
`ARGV_ARRAY_INIT`, or by calling `argv_array_init`. The `argv`
member contains the actual array; the `argc` member contains the
number of elements in the array, not including the terminating
NULL.
Functions
---------
`argv_array_init`::
Initialize an array. This is no different than assigning from
`ARGV_ARRAY_INIT`.
`argv_array_push`::
Push a copy of a string onto the end of the array.
`argv_array_pushl`::
Push a list of strings onto the end of the array. The arguments
should be a list of `const char *` strings, terminated by a NULL
argument.
`argv_array_pushf`::
Format a string and push it onto the end of the array. This is a
convenience wrapper combining `strbuf_addf` and `argv_array_push`.
`argv_array_pushv`::
Push a null-terminated array of strings onto the end of the array.
`argv_array_pop`::
Remove the final element from the array. If there are no
elements in the array, do nothing.
`argv_array_clear`::
Free all memory associated with the array and return it to the
initial, empty state.
`argv_array_detach`::
Disconnect the `argv` member from the `argv_array` struct and
return it. The caller is responsible for freeing the memory used
by the array, and by the strings it references. After detaching,
the `argv_array` is in a reinitialized state and can be pushed
into again.