Update of "Manual for lc_register_var"
Overview

Artifact ID: 13506d5d971d176beedec7c8e4d28451accdec5c
Page Name:Manual for lc_register_var
Date: 2014-11-24 20:11:50
Original User: rkeene
Parent: 084900ca0db1f0e051901d70709d0544a0fb50fa
Content

NAME

lc_register_var - Register a variable for automatic processing.

 

SYNOPSIS

#include <libconfig.h>

int lc_register_var(const char *var, lc_var_type_t type, void *data, char opt);

 

DESCRIPTION

The lc_register_var(3) function registers a variable for automatic processing. The var parameter specifies the variable name for processing. This name can exist in a configuration file, an environment variable, or on the command line. The opt parameter specifies the single letter short option that can be specified on the command line to change the value of the variable specified by the data parameter. A value of ' ' can be specified for no short option.

The type parameter is of type lc_var_type_t which specifies the type of the data parameter. Valid values for type are:

LC_VAR_STRING
For a string type variable. The data passed should be of type "char **". The data will be set to a region of memory that has been allocated with malloc() and can be released be free()'d.
LC_VAR_LONG_LONG
For a "long long" integer type variable. The data passed should be of type "long long *".
LC_VAR_LONG
For a "long" integer type variable. The data passed should be of type "long *".
LC_VAR_INT
For a "int" integer type variable. The data passed should be of type "int *".
LC_VAR_SHORT
For a "short" integer type variable. The data passed should be of type "short *".
LC_VAR_FLOAT
For a "float" floating point type variable. The data passed should be of type "float *".
LC_VAR_DOUBLE
For a "double" floating point type variable. The data passed should be of type "double *".
LC_VAR_BOOL
For a boolean type variable. The data passed should be of type "int *". When a true value is specified the variable is set to 1. When a false value is specified the variable is set to 0. Any other value sets the variable to -1. Valid true values are: enable, true, yes, on, y, and 1. Valid false values are: disable, false, off, no, n, and 0.
LC_VAR_FILENAME
Not implemented.
LC_VAR_DIRECTORY
Not implemented.
LC_VAR_SIZE_LONG_LONG
For a "long long" integer type that can have size modifiers, such as 'G' or gigabytes, 'M' for megabytes, 'K' for kilobytes. The data passed should be of type "long long *".
LC_VAR_SIZE_LONG
For a "long" integer type that can have size modifiers, such as 'G' or gigabytes, 'M' for megabytes, 'K' for kilobytes. The data passed should be of type "long *".
LC_VAR_SIZE_INT
For a "int" integer type that can have size modifiers, such as 'G' or gigabytes, 'M' for megabytes, 'K' for kilobytes. The data passed should be of type "int *".
LC_VAR_SIZE_SHORT
For a "short" integer type that can have size modifiers, such as 'G' or gigabytes, 'M' for megabytes, 'K' for kilobytes. The data passed should be of type "short *".
LC_VAR_SIZE_SIZE_T
For a "size_t" data type that can have size modifiers, such as 'G' or gigabytes, 'M' for megabytes, 'K' for kilobytes. The data passed should be of type "size_t *".
LC_VAR_TIME
Not implemented.
LC_VAR_DATE
Not implemented.
LC_VAR_BOOL_BY_EXISTANCE
This type of variable takes no arguments, it is set to true (1) by its existance in a configuration file, environment variable, or on the command line. If it is not specified, the value of the data passed is not changed. The data passed should be of type "int *".
LC_VAR_CIDR
This type of variable accepts a CIDR format netmask and IP. This is not yet implemented. (XXX)
LC_VAR_IP
This type of variable accepts an IP address in decimal-dot format. The value is stored in a uint32_t in network byte order.
LC_VAR_HOSTNAME
This type of variable accepts an address in hostname format. The value is stored in a uint32_t in network byte order.
LC_VAR_ADDR
This type of variable accepts an address in either hostname or decimal-dot format. The value is stored in a uint32_t in network byte order.

 

RETURN VALUE

On success 0 is returned, otherwise -1 is returned.

 

EXAMPLE

#include <libconfig.h>
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char **argv) {
        int lc_p_ret, lc_rv_ret;
        char *filename = NULL;
        long int counter = -1;
        lc_rv_ret = lc_register_var("Begin", LC_VAR_LONG,
                                    &counter, 'c');
        if (lc_rv_ret != 0) {
                fprintf(stderr, "Error registering variable: %i.\n",
                        lc_geterrno());
                return(EXIT_FAILURE);
        }
        lc_rv_ret = lc_register_var("File", LC_VAR_STRING,
                                    &filename, 'f');
        if (lc_rv_ret != 0) {
                fprintf(stderr, "Error registering variable: %i.\n",
                        lc_geterrno());
                return(EXIT_FAILURE);
        }
        lc_p_ret = lc_process(argc, argv, "example", LC_CONF_APACHE,
                              NULL);
        lc_cleanup();
        if (lc_p_ret != 0) {
                fprintf(stderr, "Error processing configuration: \
                        %s\n", lc_geterrstr());
                return(EXIT_FAILURE);
        }
        if (filename != NULL) {
                printf("File specified was: %s\n", filename);
        } else {
                printf("No filename specified.\n");
        }
        if (counter != -1) {
                printf("Counter was specified as: %ld\n", counter);
        } else {
                printf("Counter was not specified.\n");
        }
        return(EXIT_SUCCESS);
}

 

SEE ALSO

libconfig(3), lc_register_callback(3), lc_geterrno(3), lc_geterrstr(3), lc_seterrstr(3), lc_handle_type(3), lc_process(3), lc_process_file(3), lc_cleanup(3)