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authorEric Blake <eblake@redhat.com>2015-11-10 23:51:20 -0700
committerMarkus Armbruster <armbru@redhat.com>2015-11-11 18:56:26 +0100
commit455b0fde8c38a0794743e2e7c1a40018b7bee9f6 (patch)
tree036a4a332b5b713734b536a63987e0cb96118a6b /docs/writing-qmp-commands.txt
parent3c07587d49458341510360557c849e93e9afaf59 (diff)
error: More error_setg() usage
A few uses of error_set(ERROR_CLASS_GENERIC_ERROR) were missed in c6bd8c706, or have snuck in since. Nuke them. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1447224690-9743-19-git-send-email-eblake@redhat.com> Acked-by: Andreas Färber <afaerber@suse.de> [Indentation tidied up, commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com>
Diffstat (limited to 'docs/writing-qmp-commands.txt')
-rw-r--r--docs/writing-qmp-commands.txt20
1 files changed, 9 insertions, 11 deletions
diff --git a/docs/writing-qmp-commands.txt b/docs/writing-qmp-commands.txt
index 8647cac4e7..59aa77ae25 100644
--- a/docs/writing-qmp-commands.txt
+++ b/docs/writing-qmp-commands.txt
@@ -210,7 +210,7 @@ if you don't see these strings, then something went wrong.
=== Errors ===
QMP commands should use the error interface exported by the error.h header
-file. Basically, errors are set by calling the error_set() function.
+file. Basically, most errors are set by calling the error_setg() function.
Let's say we don't accept the string "message" to contain the word "love". If
it does contain it, we want the "hello-world" command to return an error:
@@ -219,8 +219,7 @@ void qmp_hello_world(bool has_message, const char *message, Error **errp)
{
if (has_message) {
if (strstr(message, "love")) {
- error_set(errp, ERROR_CLASS_GENERIC_ERROR,
- "the word 'love' is not allowed");
+ error_setg(errp, "the word 'love' is not allowed");
return;
}
printf("%s\n", message);
@@ -229,10 +228,8 @@ void qmp_hello_world(bool has_message, const char *message, Error **errp)
}
}
-The first argument to the error_set() function is the Error pointer to pointer,
-which is passed to all QMP functions. The second argument is a ErrorClass
-value, which should be ERROR_CLASS_GENERIC_ERROR most of the time (more
-details about error classes are given below). The third argument is a human
+The first argument to the error_setg() function is the Error pointer
+to pointer, which is passed to all QMP functions. The next argument is a human
description of the error, this is a free-form printf-like string.
Let's test the example above. Build qemu, run it as defined in the "Testing"
@@ -249,8 +246,9 @@ The QMP server's response should be:
}
}
-As a general rule, all QMP errors should use ERROR_CLASS_GENERIC_ERROR. There
-are two exceptions to this rule:
+As a general rule, all QMP errors should use ERROR_CLASS_GENERIC_ERROR
+(done by default when using error_setg()). There are two exceptions to
+this rule:
1. A non-generic ErrorClass value exists* for the failure you want to report
(eg. DeviceNotFound)
@@ -259,8 +257,8 @@ are two exceptions to this rule:
want to report, hence you have to add a new ErrorClass value so that they
can check for it
-If the failure you want to report doesn't fall in one of the two cases above,
-just report ERROR_CLASS_GENERIC_ERROR.
+If the failure you want to report falls into one of the two cases above,
+use error_set() with a second argument of an ErrorClass value.
* All existing ErrorClass values are defined in the qapi-schema.json file