ARM Compiler toolchain v4.1 for µVision Using the Compiler

Compiler Coding Practices
5.63 Compound literals in C99
ISO C99 supports compound literals. A compound literal looks like a cast followed by an
initializer. Its value is an object of the type specified in the cast, containing the elements
specified in the initializer. It is an lvalue. For example:
int *y = (int []) {1, 2, 3};
int *z = (int [3]) {1};
Note
int *y = (int []) {1, 2, 3}; is accepted by the compiler, but int y[] = (int []) {1, 2, 3};
is not accepted as a high-level (global) initialization.
In the following example source code, the compound literals are:
• (struct T) { 43, "world"}
• &(struct T) {.b = "hello", .a = 47}
• &(struct T) {43, "hello"}
• (int[]){1, 2, 3}
struct T
{
int a;
char *b;
} t2;
void g(const struct T *t);
void f()
{
int x[10];
...
}
t2 = (struct T) {43, "world"};
g(&(struct T) {.b = "hello", .a = 47});
g(&(struct T) {43, "bye"});
memcpy(x, (int[]){1, 2, 3}, 3 * sizeof(int));
5.63.1 See also
Concepts
• New language features of C99 on page 5-77.
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