Small sample program test.c

#include 
#include 

char * s1 = "011";
char * s2 = "0:30";

void process_old_arg( char*s )
{
    printf( "process_old_arg: s=%s\n", s );
}

void process_new_arg( char*s )
{
    printf( "process_new_arg: s=%s\n", s );
    char * ss = strdup(s);
    int p1 = atoi(strtok( ss, ":" ));
    int p2 = atoi(strtok( NULL, ":" ));
    printf( "p1=%d, p2=%d\n", p1, p2 );
}

void process_arg(char*s)
{
    if( strchr (s,':') )
        process_new_arg(s);
    else
        process_old_arg(s);
}

int main(int argc, char ** argv )
{
    process_arg(s1);
    process_arg(s2);
    
}

Compile and test

gcc test.c
./a.out
process_old_arg: s=011
process_new_arg: s=0:30
p1=0, p2=30