[PATCH v7 03/21] error: rename errp to errp_in where it is IN-argument

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Error **errp is almost always OUT-argument: it's assumed to be NULL, or
pointer to NULL-initialized pointer, or pointer to error_abort or
error_fatal, for callee to report error.

But very few functions instead get Error **errp as IN-argument:
it's assumed to be set (or, maybe, NULL), and callee should clean it,
or add some information.

In such cases, rename errp to errp_in.

This patch updates only error API functions. There still a few
functions with errp-in semantics, they will be updated in further
commits.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/qapi/error.h | 6 +++---
 util/error.c         | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/qapi/error.h b/include/qapi/error.h
index 3f95141a01..ad5b6e896d 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -233,13 +233,13 @@ void error_propagate_prepend(Error **dst_errp, Error *local_err,
  * Prepend some text to @errp's human-readable error message.
  * The text is made by formatting @fmt, @ap like vprintf().
  */
-void error_vprepend(Error **errp, const char *fmt, va_list ap);
+void error_vprepend(Error *const *errp, const char *fmt, va_list ap);
 
 /*
  * Prepend some text to @errp's human-readable error message.
  * The text is made by formatting @fmt, ... like printf().
  */
-void error_prepend(Error **errp, const char *fmt, ...)
+void error_prepend(Error *const *errp, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 
 /*
@@ -256,7 +256,7 @@ void error_prepend(Error **errp, const char *fmt, ...)
  * May be called multiple times.  The resulting hint should end with a
  * newline.
  */
-void error_append_hint(Error **errp, const char *fmt, ...)
+void error_append_hint(Error *const *errp, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
 
 /*
diff --git a/util/error.c b/util/error.c
index d4532ce318..b6c89d1412 100644
--- a/util/error.c
+++ b/util/error.c
@@ -121,7 +121,7 @@ void error_setg_file_open_internal(Error **errp,
                               "Could not open '%s'", filename);
 }
 
-void error_vprepend(Error **errp, const char *fmt, va_list ap)
+void error_vprepend(Error *const *errp, const char *fmt, va_list ap)
 {
     GString *newmsg;
 
@@ -136,7 +136,7 @@ void error_vprepend(Error **errp, const char *fmt, va_list ap)
     (*errp)->msg = g_string_free(newmsg, 0);
 }
 
-void error_prepend(Error **errp, const char *fmt, ...)
+void error_prepend(Error *const *errp, const char *fmt, ...)
 {
     va_list ap;
 
@@ -145,7 +145,7 @@ void error_prepend(Error **errp, const char *fmt, ...)
     va_end(ap);
 }
 
-void error_append_hint(Error **errp, const char *fmt, ...)
+void error_append_hint(Error *const *errp, const char *fmt, ...)
 {
     va_list ap;
     int saved_errno = errno;
-- 
2.21.0