X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/e63124bc579bfd97cfe2f620ddd84df9f20477d8..31d0247cc58abc0b0720aa7e9972011c5a66995c:/utils/gprintf.h

diff --git a/utils/gprintf.h b/utils/gprintf.h
index 9e32338..8c0f87c 100644
--- a/utils/gprintf.h
+++ b/utils/gprintf.h
@@ -45,8 +45,8 @@
 struct gprintf_ops {
   int (*putch)(void */*out*/, int /*ch*/);
   int (*putm)(void */*out*/, const char */*p*/, size_t /*sz*/);
-  PRINTF_LIKE(3, 4) int (*nputf)
-    (void */*out*/, size_t /*maxsz*/, const char */*p*/, ...);
+  PRINTF_LIKE(3, 4)
+    int (*nputf)(void */*out*/, size_t /*maxsz*/, const char */*p*/, ...);
 };
 
 extern const struct gprintf_ops file_printops;
@@ -82,9 +82,36 @@ extern int vgprintf(const struct gprintf_ops */*ops*/, void */*out*/,
  *		for @dstr_putf@, for example.
  */
 
-extern int PRINTF_LIKE(3, 4)
-  gprintf(const struct gprintf_ops */*ops*/, void */*out*/,
-	  const char */*p*/, ...);
+extern PRINTF_LIKE(3, 4)
+  int gprintf(const struct gprintf_ops */*ops*/, void */*out*/,
+	      const char */*p*/, ...);
+
+/* --- @gprintf_memputf@ --- *
+ *
+ * Arguments:	@char **buf_inout@ = address of output buffer pointer
+ *		@size_t *sz_inout@ = address of buffer size
+ *		@size_t maxsz@ = buffer size needed for this operation
+ *		@const char *p@ = pointer to format string
+ *		@va_list *ap@ = captured format-arguments tail
+ *
+ * Returns:	The formatted length.
+ *
+ * Use:		Generic utility for mostly implementing the @nputf@ output
+ *		function, if you don't have a better option.
+ *
+ *		On entry, @*buf_inout@ should be null or a buffer pointer,
+ *		with @*sz_inout@ either zero or the buffer's size,
+ *		respectively.  On exit, @*buf_input@ and @*sz_inout@ will be
+ *		updated, if necessary, to describe a sufficiently large
+ *		buffer, and the formatted string will have been written to
+ *		the buffer.
+ *
+ *		When the buffer is no longer required, free it using @xfree@.
+ */
+
+extern size_t gprintf_memputf(char **/*buf_inout*/, size_t */*sz_inout*/,
+			      size_t /*maxsz*/,
+			      const char */*p*/, va_list /*ap*/);
 
 /*----- That's all, folks -------------------------------------------------*/