struct/buf.3.in: Correct the type of `buf_put' in the synopsis.

[mLib] / utils / gprintf.h

diff --git a/utils/gprintf.h b/utils/gprintf.h
index 9e32338827690f0a4534f4a506a00e2b301a6d27..bcef7bb2d3f63fff13738152454ef60c7090284a 100644 (file)
--- a/utils/gprintf.h
+++ b/utils/gprintf.h
@@ -36,6 +36,10 @@
 
 #include <stdarg.h>
 
+#ifndef MLIB_ARENA_H
+#  include "arena.h"
+#endif
+
 #ifndef MLIB_MACROS_H
 #  include "macros.h"
 #endif
@@ -45,46 +49,70 @@
 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;
 
 /*----- Functions provided ------------------------------------------------*/
 
-/* --- @vgprintf@ --- *
+/* --- @gprintf@, @vgprintf@ --- *
  *
  * Arguments:  @const struct gprintf_ops *ops@ = output operations
  *             @void *out@ = context for output operations
  *             @const char *p@ = pointer to @printf@-style format string
- *             @va_list *ap@ = argument handle
+ *             @...@ = format arguments
+ *             @va_list *ap@ = captured format-arguments tail
  *
  * Returns:    The number of characters written to the string.
  *
- * Use:                As for @gprintf@, but takes a reified argument tail.
+ * Use:                Formats a @printf@-like message and writes the result using
+ *             the given output operations.  This is the backend machinery
+ *             for @dstr_putf@, for example.
+ *
+ *             The @gprintf@ function receives its format arguments as a
+ *             variable-length argument tail; the @vgprintf@ function
+ *             receives them as %%\emph{a pointer to}%% a captured argument
+ *             tail; it updates @*ap@, leaving it ready to read the next
+ *             unused argument.
  */
 
+extern PRINTF_LIKE(3, 4)
+  int gprintf(const struct gprintf_ops */*ops*/, void */*out*/,
+             const char */*p*/, ...);
 extern int vgprintf(const struct gprintf_ops */*ops*/, void */*out*/,
                    const char */*p*/, va_list */*ap*/);
 
-/* --- @gprintf@ --- *
+/* --- @gprintf_memputf@ --- *
  *
- * Arguments:  @const struct gprintf_ops *ops@ = output operations
- *             @void *out@ = context for output operations
- *             @const char *p@ = pointer to @printf@-style format string
- *             @...@ = argument handle
+ * Arguments:  @arena *a@ = memory allocation arena
+ *             @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 number of characters written to the string.
+ * Returns:    The formatted length.
  *
- * Use:                Formats a @printf@-like message and writes the result using
- *             the given output operations.  This is the backend machinery
- *             for @dstr_putf@, for example.
+ * 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
+ *             @x_free@.
  */
 
-extern int PRINTF_LIKE(3, 4)
-  gprintf(const struct gprintf_ops */*ops*/, void */*out*/,
-         const char */*p*/, ...);
+extern size_t gprintf_memputf(arena */*a*/,
+                             char **/*buf_inout*/, size_t */*sz_inout*/,
+                             size_t /*maxsz*/,
+                             const char */*p*/, va_list /*ap*/);
 
 /*----- That's all, folks -------------------------------------------------*/