X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Ftalloc%2F_info;fp=ccan%2Ftalloc%2F_info;h=95c91536b3fafa98d9cac86917d248d7c5bbbbd7;hb=570c9c555f076e74f46141bb42b5d1d7ac89f632;hp=0000000000000000000000000000000000000000;hpb=8f61c0bccb152b2365baf70deac1e59264d7feb7;p=ccan

diff --git a/ccan/talloc/_info b/ccan/talloc/_info
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+#include <stdio.h>
+#include <string.h>
+#include "config.h"
+
+/**
+ * talloc - tree allocator routines
+ *
+ * Talloc is a hierarchical memory pool system with destructors: you keep your
+ * objects in heirarchies reflecting their lifetime.  Every pointer returned
+ * from talloc() is itself a valid talloc context, from which other talloc()s
+ * can be attached.  This means you can do this:
+ *
+ *  struct foo *X = talloc(mem_ctx, struct foo);
+ *  X->name = talloc_strdup(X, "foo");
+ *
+ * and the pointer X->name would be a "child" of the talloc context "X" which
+ * is itself a child of mem_ctx.  So if you do talloc_free(mem_ctx) then it is
+ * all destroyed, whereas if you do talloc_free(X) then just X and X->name are
+ * destroyed, and if you do talloc_free(X->name) then just the name element of
+ * X is destroyed.
+ *
+ * If you think about this, then what this effectively gives you is an n-ary
+ * tree, where you can free any part of the tree with talloc_free().
+ *
+ * Talloc has been measured with a time overhead of around 4% over glibc
+ * malloc, and 48/80 bytes per allocation (32/64 bit).
+ *
+ * This version is based on svn://svnanon.samba.org/samba/branches/SAMBA_4_0/source/lib/talloc revision 23158.
+ *
+ * Example:
+ *	#include <stdio.h>
+ *	#include <stdarg.h>
+ *	#include <err.h>
+ *	#include <ccan/talloc/talloc.h>
+ *
+ *	// A structure containing a popened command.
+ *	struct command
+ *	{
+ *		FILE *f;
+ *		const char *command;
+ *	};
+ *
+ *	// When struct command is freed, we also want to pclose pipe.
+ *	static int close_cmd(struct command *cmd)
+ *	{
+ *		pclose(cmd->f);
+ *		// 0 means "we succeeded, continue freeing"
+ *		return 0;
+ *	}
+ *
+ *	// This function opens a writable pipe to the given command.
+ *	struct command *open_output_cmd(const void *ctx, char *fmt, ...)
+ *	{
+ *		va_list ap;
+ *		struct command *cmd = talloc(ctx, struct command);
+ *
+ *		if (!cmd)
+ *			return NULL;
+ *
+ *		va_start(ap, fmt);
+ *		cmd->command = talloc_vasprintf(cmd, fmt, ap);
+ *		va_end(ap);
+ *		if (!cmd->command) {
+ *			talloc_free(cmd);
+ *			return NULL;
+ *		}
+ *
+ *		cmd->f = popen(cmd->command, "w");
+ *		if (!cmd->f) {
+ *			talloc_free(cmd);
+ *			return NULL;
+ *		}
+ *		talloc_set_destructor(cmd, close_cmd);
+ *		return cmd;
+ *	}
+ *
+ *	int main(int argc, char *argv[])
+ *	{
+ *		struct command *cmd;
+ *
+ *		if (argc != 2)
+ *			errx(1, "Usage: %s <command>\n", argv[0]);
+ *
+ *		cmd = open_output_cmd(NULL, "%s hello", argv[1]);
+ *		if (!cmd)
+ *			err(1, "Running '%s hello'", argv[1]);
+ *		fprintf(cmd->f, "This is a test\n");
+ *		talloc_free(cmd);
+ *		return 0;
+ *	}
+ *
+ * Licence: GPL (2 or any later version)
+ */
+int main(int argc, char *argv[])
+{
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/typesafe_cb\n");
+		return 0;
+	}
+
+	return 1;
+}