There is no standard way in C to parse config files. Several libraries have sprung up to solve the problem, but perhaps that is overkill for what should be a simple operation.<\/p>\n
Presenting: cfg_parse – a compile-in solution for reading key-value pairs from file(s), looking up settings, and writing a config file back to disk. I could write more about it, but the included main.c shows all the functionality.<\/p>\n
#include \"cfg_parse.h\"<\/p>\n #include <stdio.h><\/p>\n int main(int argc, char **argv) \/\/ Initialize config struct \/\/ Specifying some defaults \/\/ \"Required\" file \/\/ Several \"optional\" files can be added as well \/\/ Retrieve the value for key INFINITY, and print \/\/ Retrieve the value for key \"KEY\", and print \/\/ Delete the key-value pair for \"DELETE_ME\" \/\/ Dump cfg-struct to disk. \/\/ All done, clean up. return 0;\/\/ driver test program for cfg_parse<\/p>\n
\n{
\n\/\/ Pointer to a cfg_struct structure
\nstruct cfg_struct *cfg;<\/p>\n
\ncfg = cfg_init();<\/p>\n
\ncfg_set(cfg,\"KEY\",\"VALUE\");
\ncfg_set(cfg,\"KEY_A\",\"DEFAULT_VALUE_A\");<\/p>\n
\nif (cfg_load(cfg,\"config.ini\") < 0)
\n{
\nfprintf(stderr,\"Unable to load cfg.ini\\n\");
\nreturn -1;
\n}<\/p>\n
\n\/\/ \u00a0Each subsequent call upserts values already in
\n\/\/ \u00a0the cfg structure.
\ncfg_load(cfg,\"\/usr\/local\/etc\/config.ini\");
\ncfg_load(cfg,\"~\/.config\");<\/p>\n
\nprintf(\"INFINITY = %s\\n\",cfg_get(cfg,\"INFINITY\"));<\/p>\n
\nprintf(\"KEY = %s\\n\",cfg_get(cfg,\"KEY\"));<\/p>\n
\ncfg_delete(cfg,\"DELETE_ME\");<\/p>\n
\ncfg_save(cfg,\"config_new.ini\");<\/p>\n
\ncfg_free(cfg);<\/p>\n
\n}<\/code><\/p>\n