openairinterface5g/common/config/DOC/config/devusage/api.md

configmodule_interface_t *load_configmodule(int argc, char **argv)

• Parses the command line options, looking for the –O argument
• Loads the libparams_<configsource>.so (today libparams_libconfig.so) shared library
• Looks for config_<config source>_init symbol and calls it , passing it an array of string corresponding to the « : » separated strings used in the –O option
• Looks for config_<config source>_get, config_<config source>_getlist and config_<config source>_end symbols which are the three functions a configuration library should implement. Get and getlist are mandatory, end is optional.
• Stores all the necessary information in a configmodule_interface_t structure, which is of no use for caller as long as we only use one configuration source.

void End_configmodule(void)

• Free memory which has been allocated by the configuration module since its initialization.
• Possibly calls the config_<config source>_end function

int config_get(paramdef_t *params,int numparams, char *prefix)

• Reads as many parameters as described in params, they must all be in the same configuration file section
• Calls the config_<config source>_get function
• Calls the config_process_cmdline function
• params points to an array of paramdef_t structures which describes the parameters to be read, possibly including a pointer to a checking function. The following bits can possibly be set in the paramflags mask before calling

• PARAMFLAG_MANDATORY: -1 is returned if the parameter is not explicitly defined in the config source.
• PARAMFLAG_DISABLECMDLINE: parameter cannot be modified via the command line
• PARAMFLAG_DONOTREAD: ignore the parameter, can be used at run-time, to alter a pre-defined paramdef_t array which is used in several config_get or/and config_getlist calls.
• PARAMFLAG_NOFREE: do not free the memory possibly allocated by the config module to store the value of the parameter. Default behavior is for the config module to free the memory it has allocated when the config_end function is called.
• PARAMFLAG_BOOL: Only relevant for integer types. tell the config module that when processing the command line, the corresponding option can be specified without any arggument and that in this case it must set the value to 1.

• params is also used as an output parameter, < XXX >ptr > field is used by the config module to store the value it has read. The following bits can possibly be set in the paramflags mask after the call:
  • PARAMFLAG_MALLOCINCONFIG: memory has been allocated for the < XXX >ptr > field
  • PARAMFLAG_PARAMSET: parameter has been found in the config source, it is not set to default value.
  • PARAMFLAG_PARAMSET: parameter has been set to its default value
• numparams is the number of entries in the params array
• prefix is a character string to be appended to the parameters name, it defines the parameters position in the configuration file hierarchy (the section name in libconfig terminology).
• The returned value is the number of parameters which have been assigned a value or -1 if a severe error occured

int config_libconfig_getlist(paramlist_def_t *ParamList, paramdef_t *params, int numparams, char *prefix)

• Reads multiple occurrences of a parameters array
• Calls the config_<config source>_get function for each list occurrence
• params points to an array of paramdef_t structures which describes the parameters in each occurrence of the list
• ParamList points to a structure, where paramarray field points to an array of paramdef_t structure, allocated by the function. It is used to return the values of the parameters.
• The returned value is the number of occurrences in the list or -1 in case of severe error

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