Added vasprintf.c

vasprintf.c

@@ -0,0 +1,27 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+ 
+void test(const char *fmt, ...)
+{
+    char* dyn_buf;
+ 
+    printf("Demo asprintf:\n");
+    const int written_1 = asprintf(&dyn_buf, "%s", fmt);
+    printf("dyn_buf: \"%s\"; %i chars were written\n", dyn_buf, written_1);
+    free(dyn_buf);
+ 
+    printf("Demo vasprintf:\n");
+    va_list args;
+    va_start(args, fmt);
+    const int written_2 = vasprintf(&dyn_buf, fmt, args);
+    va_end(args);
+    printf("dyn_buf: \"%s\"; %i chars were written\n", dyn_buf, written_2);
+    free(dyn_buf);
+}
+ 
+int main(void)
+{
+    test("Testing... %d, %d, %d", 1, 2, 3);
+}