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

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)