diff options
Diffstat (limited to 'docs/writing-qmp-commands.txt')
| -rw-r--r-- | docs/writing-qmp-commands.txt | 20 |
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 |