File Exists

#include <unistd.h>
int file_exist(const char* filename)
{
    if( access( filename, F_OK ) == 0 )
        return 1; //exist
    else
        return 0;
}

2. stat

#include <sys/stat.h>
/*
 * return 0 if the file exist, otherwise return 1
 */
int file_exist(const char* filename){
    struct stat buffer;
    int exist = stat(filename,&buffer);
    if(exist == 0)
        return 0;
    else // -1
        return 1;
}

3. glob_t

#include <glob.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>

int main (void)
{
    glob_t globfiles;

    glob("/home/ubuntu/*.wav", 0, NULL, &globfiles);

    printf("%ld\n", globfiles.gl_pathc);
    int i=0;
    for(i=0;i<globfiles.gl_pathc;i++)
    {
        //int fd = open(globfiles.gl_pathv[0], O_RDONLY);
        printf("%s\n", globfiles.gl_pathv[i]);
    }
    globfree(&globfiles);
    return 0;
}