diff options
Diffstat (limited to 'servicecmd/servicecmd.h')
| -rw-r--r-- | servicecmd/servicecmd.h | 50 |
1 files changed, 46 insertions, 4 deletions
diff --git a/servicecmd/servicecmd.h b/servicecmd/servicecmd.h index ce5e58f..27204d0 100644 --- a/servicecmd/servicecmd.h +++ b/servicecmd/servicecmd.h @@ -1,3 +1,20 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +/* + * Copyright (C) 2018 - David Oberhollenzer + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + */ #ifndef SERVICECMD_H #define SERVICECMD_H @@ -8,21 +25,46 @@ #include "util.h" +/* + Describes a command that can be launched by passing its name as + second command line argument to the main() function (i.e. immediately + after the actual program name). + + Short and long descriptions can be provided to print out help text. + + The main() function calls into a callback in this structure to execute + the command. +*/ typedef struct command_t { struct command_t *next; - const char *cmd; - const char *usage; - const char *s_desc; - const char *l_desc; + const char *cmd; /* command name */ + const char *usage; /* list of possible arguments */ + const char *s_desc; /* short description used by help */ + const char *l_desc; /* long description used by help */ + /* + Semantics are the same as for main(). Called from main() + function with first argument (i.e. top level program name) + removed. + */ int (*run_cmd)(int argc, char **argv); } command_t; +/* Global list of available commands */ extern command_t *commands; +/* + Implemented in servicecmd.c. Prints program usage message and + terminates with the given exit status. +*/ void usage(int status) NORETURN; +/* + To implement a new command, add a global, static instance of a + command_t (or derived) structure to a C file and pass it to this + macro to have it automatically registered on program startup. +*/ #define REGISTER_COMMAND(cmd) \ static void __attribute__((constructor)) register_##cmd(void) \ { \ |