1. This function sends an error message to the error output stream of the model corresponding to the given context. If the context provided is NULL, the messages goes to the global error output stream of Mosel. The parameters expected by this fonction correspond to those of the standard C function printf. The special format %r can also be used to display real values: it implies the use of the format specified by control parameter realfmt (see getparam).

2. An error stream is always available even before and after execution of the model.