Does C have a "foreach" loop construct?

Almost all languages have a foreach loop or something similar. Does C have one? Can you post some example code?

C doesn't have a foreach, but macros are frequently used to emulate that:

#define for_each_item(item, list) \
    for(T * item = list->head; item != NULL; item = item->next)

And can be used like

for_each_item(i, processes) {
    i->wakeup();
}

Iteration over an array is also possible:

#define foreach(item, array) \
    for(int keep = 1, \
            count = 0,\
            size = sizeof (array) / sizeof *(array); \
        keep && count != size; \
        keep = !keep, count++) \
      for(item = (array) + count; keep; keep = !keep)

And can be used like

int values[] = { 1, 2, 3 };
foreach(int *v, values) {
    printf("value: %d\n", *v);
}

Edit: In case you are also interested in C++ solutions, C++ has a native for-each syntax called "range based for"

Here is a full program example of a for-each macro in C99:

#include <stdio.h>

typedef struct list_node list_node;
struct list_node {
    list_node *next;
    void *data;
};

#define FOR_EACH(item, list) \
    for (list_node *(item) = (list); (item); (item) = (item)->next)

int
main(int argc, char *argv[])
{
    list_node list[] = {
        { .next = &list[1], .data = "test 1" },
        { .next = &list[2], .data = "test 2" },
        { .next = NULL,     .data = "test 3" }
    };

    FOR_EACH(item, list)
        puts((char *) item->data);

    return 0;
}