documentation

shm.c

@@ -1,56 +0,0 @@
-#define _POSIX_C_SOURCE 200809L
-#include <errno.h>
-#include <fcntl.h>
-#include <string.h>
-#include <sys/mman.h>
-#include <time.h>
-#include <unistd.h>
-
-/**
- * Boilerplate to create an in-memory shared file.
- *
- * Link with `-lrt`.
- */
-
-static void randname(char *buf) {
-	struct timespec ts;
-	clock_gettime(CLOCK_REALTIME, &ts);
-	long r = ts.tv_nsec;
-	for (int i = 0; i < 6; ++i) {
-		buf[i] = 'A'+(r&15)+(r&16)*2;
-		r >>= 5;
-	}
-}
-
-static int anonymous_shm_open(void) {
-	char name[] = "/hello-wayland-XXXXXX";
-	int retries = 100;
-
-	do {
-		randname(name + strlen(name) - 6);
-
-		--retries;
-		// shm_open guarantees that O_CLOEXEC is set
-		int fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
-		if (fd >= 0) {
-			shm_unlink(name);
-			return fd;
-		}
-	} while (retries > 0 && errno == EEXIST);
-
-	return -1;
-}
-
-int create_shm_file(off_t size) {
-	int fd = anonymous_shm_open();
-	if (fd < 0) {
-		return fd;
-	}
-
-	if (ftruncate(fd, size) < 0) {
-		close(fd);
-		return -1;
-	}
-
-	return fd;
-}