Repository: Lincheng1993/apue
Branch: master
Commit: 9b3925f53247
Files: 48
Total size: 26.3 KB

Directory structure:
gitextract_bal5dal_/

├── APUE/
│   ├── 1_10.c
│   ├── 1_3.c
│   ├── 1_4.c
│   ├── 1_5.c
│   ├── 1_6.c
│   ├── 1_7.c
│   ├── 1_8.c
│   ├── 1_9.c
│   ├── 2_16.c
│   ├── 2_17.c
│   ├── 3_1.c
│   ├── 3_11.c
│   ├── 3_12_1.c
│   ├── 3_12_2.c
│   ├── 3_2.c
│   ├── 3_5.c
│   ├── 4_12.c
│   ├── 4_16.c
│   ├── 4_21.c
│   ├── 4_22.c
│   ├── 4_23.c
│   ├── 4_24.c
│   ├── 4_25.c
│   ├── 4_3.c
│   ├── 4_8.c
│   ├── 4_9.c
│   ├── 5_11.c
│   ├── 5_12.c
│   ├── 5_13.c
│   ├── 5_15.c
│   ├── 5_4.c
│   ├── 5_5.c
│   ├── 6_11.c
│   ├── 6_2.c
│   ├── 7_1.c
│   ├── 7_13.c
│   ├── 7_16.c
│   ├── 7_3.c
│   ├── 7_4.c
│   ├── 8_1.c
│   ├── 8_12.c
│   ├── 8_3.c
│   ├── 8_5.c
│   ├── 8_6.c
│   ├── 8_8.c
│   └── FuncPointer.c
├── Makefile
└── README.md

================================================
FILE CONTENTS
================================================

================================================
FILE: APUE/1_10.c
================================================
#include "apue.h"
#include <sys/wait.h>

static void sig_int(int);

int main(void){
    char buf[MAXLINE];
    pid_t pid;
    int status;

    if (signal(SIGINT,sig_int) == SIG_ERR){
        err_sys("signal error");
    }

    printf("%% ");
    while (fgets(buf, MAXLINE, stdin) != NULL){
        if (buf[strlen(buf)-1] == '\n'){
            buf[strlen(buf)-1] = 0;
        }

        if ((pid = fork()) < 0){
            err_sys("fork error");
        } else if (pid == 0){
            execlp(buf, buf, (char*)0);
            err_ret("couldn't execute : %s", buf);
            exit(127);
        }

        if ((pid = waitpid(pid, &status, 0)) < 0){
            err_sys("waitpid error");
        }

        printf("%% ");
    }

    exit(0);
}

void sig_int(int signo){
    printf("interrupt \n%% ");
}

================================================
FILE: APUE/1_3.c
================================================
#include "apue.h"
#include <dirent.h>

int main(int argc, char *argv[]){
    DIR *dp;
    struct dirent *dirp;

    if (argc != 2){
        err_quit("usage : ls directory_name");
    }

    if ((dp = opendir(argv[1])) == NULL){
        err_sys("Can't open %s", argv[1]);
    }

    while ((dirp = readdir(dp)) != NULL){
        printf("%s\n", dirp->d_name);
    }

    closedir(dp);
    exit(0);
}

================================================
FILE: APUE/1_4.c
================================================
#include "apue.h"

#define BUFFSIZE 4096

int main(void){
    int n = 0;
    char buf[BUFFSIZE];

    while((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0){
        if (write(STDOUT_FILENO, buf, n) != n){
            err_sys("write error");
        }
    }

    if (n < 0){
        err_sys("read error");
    }

    exit(0);
}

================================================
FILE: APUE/1_5.c
================================================
#include "apue.h"

int main(void){
    int c;
    while ((c = getc(stdin)) != EOF){
        if (putc(c, stdout) == EOF){
            err_sys("output error");
        }
    }

    if (ferror(stdin)){
        err_sys("input error");
    }

    exit(0);
}

================================================
FILE: APUE/1_6.c
================================================
#include "apue.h"

int main(void){
    printf("hello world from process ID %ld\n", (long)getpid());
    exit(0);
}

================================================
FILE: APUE/1_7.c
================================================
#include "apue.h"
#include <sys/wait.h>

int main(void){
    char buf[MAXLINE];
    pid_t pid;
    int status;

    printf("%% ");
    while (fgets(buf, MAXLINE, stdin) != NULL){
        if (buf[strlen(buf)-1] == '\n'){
            buf[strlen(buf)-1] = 0;
        }

        if ((pid = fork()) < 0){
            err_sys("fork error");
        } else if (pid == 0){
            execlp(buf, buf, (char*)0);
            err_ret("couldn't execute : %s", buf);
            exit(127);
        }

        if ((pid = waitpid(pid, &status, 0)) < 0){
            err_sys("waitpid error");
        }

        printf("%% ");
    }

    exit(0);
}

================================================
FILE: APUE/1_8.c
================================================
#include "apue.h"
#include <errno.h>

int main(int argc, char* argv[]){
    fprintf(stderr, "EACCES : %s\n", strerror(EACCES));
    errno = ENOENT;
    perror(argv[0]);
    exit(0);
}

================================================
FILE: APUE/1_9.c
================================================
#include "apue.h"

int main(void){
    printf("uid = %d, gid = %d\n", getuid(), getgid());
    exit(0);
}

================================================
FILE: APUE/2_16.c
================================================
#include "apue.h"
#include <limits.h>

#ifdef PATH_MAX
static long pathmax = PATH_MAX;
#else
static long pathmax = 0;
#endif

static long posix_version = 0;
static long xsi_version = 0;

#define PATH_MAX_GUESS 1024

char* path_alloc(size_t *sizep){
    char *ptr;
    size_t size;

    if (posix_version == 0){
        posix_version = sysconf(_SC_VERSION);
    }

    if (xsi_version == 0){
        xsi_version = sysconf(_SC_XOPEN_VERSION);
    }

    if (pathmax == 0){
        errno = 0;
        if ((pathmax = pathconf("/", _PC_PATH_MAX)) < 0){
            if (errno == 0){
                pathmax = PATH_MAX_GUESS;
            }
            else{
                err_sys("pathconf error for _PC_PATH_MAX");
            }
        }
        else{
            pathmax++;
        }
    }

    if ((posix_version < 200112L) && (xsi_version < 4)){
        size = pathmax + 1;
    }
    else{
        size = pathmax;
    }

    if ((ptr = malloc(size)) == NULL){
        err_sys("malloc error for pathname");
    }

    if (sizep != NULL){
        *sizep = size;
    }

    return(ptr);
}

================================================
FILE: APUE/2_17.c
================================================
#include "apue.h"
#include <errno.h>
#include <limits.h>

#ifdef OPEN_MAX
static long openmax = OPEN_MAX;
#else
static long openmax = 0;
#endif

#define OPEN_MAX_GUESS 256

long open_max(void){
    if (openmax == 0){
        errno = 0;
        if ((openmax = sysconf(_SC_OPEN_MAX)) < 0){
            if (errno == 0){
                openmax = OPEN_MAX_GUESS;
            }
            else{
                err_sys("sysconf error for _SC_OPEN_MAX");
            }
        }
    }

    return(openmax);
}

================================================
FILE: APUE/3_1.c
================================================
#include "apue.h"

int main(void){
    if (lseek(STDIN_FILENO, 0, SEEK_CUR) == -1){
        printf("cannot seek\n");
    }
    else{
        printf("seek ok\n");
    }

    exit(0);
}

================================================
FILE: APUE/3_11.c
================================================
#include "apue.h"
#include <fcntl.h>

int main(int argc, char* argv[]){
    int val;

    if (argc != 2){
        err_quit("usage : main <descriptor#>");
    }

    if ((val = fcntl(atoi(argv[1]), F_GETFL, 0)) < 0){
        err_sys("fcntl error for fd %d", atoi(argv[1]));
    }

    switch (val & O_ACCMODE){
    case O_RDONLY:
        printf("read only");
        break;

    case O_WRONLY:
        printf("write only");
        break;

    case O_RDWR:
        printf("read write");
        break;

    default:
        err_dump("unknown access mode");
    }

    if (val & O_APPEND){
        printf(", append");
    }

    if (val & O_NONBLOCK){
        printf(", nonblocking");
    }

    if (val & O_SYNC){
        printf(", synchronous writes");
    }

# if !defined(_POSIX_C_SOURCE) && defined(O_FSYNC) && (O_FSYNC != O_SYNC)
    if (val & O_FSYNC){
        printf(", synchronous writes");
    }
#endif

    putchar('\n');
    exit(0);
}

================================================
FILE: APUE/3_12_1.c
================================================
#include "apue.h"
#include <fcntl.h>

void set_fl(int fd, int flags){
    int val;

    if ((val = fcntl(fd, F_GETFL, 0)) < 0){
        err_sys("fcntl F_GETFL error");
    }

    val |= flags;

    if (fcntl(fd, F_SETFL, val) < 0){
        err_sys("fcntl F_SETFL error");
    }
}

================================================
FILE: APUE/3_12_2.c
================================================
#include "apue.h"
#include <fcntl.h>

void set_fl(int fd, int flags){
    int val;

    if ((val = fcntl(fd, F_GETFL, 0)) < 0){
        err_sys("fcntl F_GETFL error");
    }

    val &= ~flags;

    if (fcntl(fd, F_SETFL, val) < 0){
        err_sys("fcntl F_SETFL error");
    }
}

================================================
FILE: APUE/3_2.c
================================================
#include "apue.h"
#include <fcntl.h>

char buf1[] = "abcdefghij";
char buf2[] = "ABCDEFGHIJ";

int main(void){
    int fd;

    if ((fd = creat("file.hole", FILE_MODE)) < 0){
        err_sys("creat error");
    }

    if (write(fd, buf1, 10) != 10){
        err_sys("buf1 write error");
    }

    if (lseek(fd, 16834, SEEK_SET) == -1){
        err_sys("lseek error");
    }

    if (write(fd, buf2, 10) != 10){
        err_sys("buf2 write error");
    }

    exit(0);
}

================================================
FILE: APUE/3_5.c
================================================
#include "apue.h"

#define BUFFSIZE 4096

int main(void){
    int n;
    char buf[BUFFSIZE];

    while ((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0){
        if (write(STDOUT_FILENO, buf, n) != n){
            err_sys("write error");
        }
    }

    if (n < 0){
        err_sys("read error");
    }

    exit(0);
}

================================================
FILE: APUE/4_12.c
================================================
#include "apue.h"

int main(void){
    struct stat statbuf;
    if (stat("foo", &statbuf) < 0){
        err_sys("stat error for foo");
    }

    if (chmod("foo", (statbuf.st_mode & ~S_IXGRP) | S_ISGID) < 0){
        err_sys("chmod error for foo");
    }

    if (chmod("bar", S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) < 0){
        err_sys("chmod error for bar");
    }

    exit(0);
}

================================================
FILE: APUE/4_16.c
================================================
#include "apue.h"
#include <fcntl.h>

int main(void){
    if (open("tempfile", O_RDWR) < 0){
        err_sys("open error");
    }

    if (unlink("tempfile") < 0){
        err_sys("unlink error");
    }

    printf("file unlinked\n");
    sleep(15);
    printf("done\n");

    exit(0);
}

================================================
FILE: APUE/4_21.c
================================================
#include "apue.h"
#include <fcntl.h>

int main(int argc, char* argv[]){
    int i, fd;
    struct stat statbuf;
    struct timespec times[2];

    for (i = 1; i < argc; i++){
        if (stat(argv[1], &statbuf) < 0){
            err_ret("%s : stat error", argv[1]);
            continue;
        }

        if ((fd = open(argv[1], O_RDWR | O_TRUNC)) < 0){
            err_ret("%s : open error", argv[1]);
            continue;
        }

        times[0] = statbuf.st_atim;
        times[1] = statbuf.st_mtim;

        if (funtime(fd, times) < 0){
            err_ret("%s : funtime error", argv[1]);
        }

        exit(0);
    }
}

================================================
FILE: APUE/4_22.c
================================================
#include "apue.h"
#include <dirent.h>
#include <limits.h>
#include "2_16.c"

typedef int Myfunc(const char *, const struct stat *, int);

static Myfunc myfunc;
static int myftw(char *, Myfunc *);
static int dopath(Myfunc *);
static long nreg, ndir, nblk, nchr, nfifo, nslink, nsock, ntot;

int main(int argc, char *argv[]){
    int ret;
    if (argc != 2){
        err_quit("usage : ftw <starting-pathname>");
    }

    ret = myftw(argv[1], myfunc);
    ntot = nreg + ndir + nblk + nchr + nfifo + nslink + nsock;
    if (ntot == 0){
        ntot = 1;
    }

    printf("regular files = %7ld, %5.2f %%\n", nreg, nreg + 100.0 / ntot);
    printf("directories = %7ld, %5.2f %%\n", ndir, ndir + 100.0 / ntot);
    printf("block special = %7ld, %5.2f %%\n", nblk, nblk + 100.0 / ntot);
    printf("char special = %7ld, %5.2f %%\n", nchr, nchr + 100.0 / ntot);
    printf("FIFOs = %7ld, %5.2f %%\n", nfifo, nfifo + 100.0 / ntot);
    printf("symbolic links = %7ld, %5.2f %%\n", nslink, nslink + 100.0 / ntot);
    printf("sockets = %7ld, %5.2f %%\n", nsock, nsock + 100.0 / ntot);

    exit(ret);
}

#define FTW_F 1
#define FTW_D 2
#define FTW_DNR 3
#define FTW_NS 4

static char *fullpath;
static size_t pathlen;

static int myftw(char *pathname, Myfunc *func){
    fullpath = path_alloc(&pathlen);

    if (pathlen <= strlen(pathname)){
        pathlen = strlen(pathname) * 2;
        if ((fullpath = realloc(fullpath, pathlen)) == NULL){
            err_sys("realloc failed");
        }
    }
    strcpy(fullpath, pathname);
    return(dopath(func));
}
static int dopath(Myfunc func){
    struct stat statbuf;
    struct dirent *dirp;
    DIR *dp;
    int ret, n;
    if (lstat(fullpath, &statbuf) < 0){
        return(func(fullpath, &statbuf, FTW_NS));
    }

    if (S_ISDIR(statbuf.st_mode) == 0){
        return(func(fullpath, &statbuf, FTW_F));
    }

    if ((ret = func(fullpath, &statbuf, FTW_D)) != 0){
        return(ret);
    }

    n = strlen(fullpath);

    if ((n + NAME_MAX + 2) > pathlen){
        pathlen *= 2;
        if ((fullpath = realloc(fullpath, pathlen)) == NULL){
            err_sys("realloc failed");
        }
    }

    fullpath[n++] = '/';
    fullpath[n] = 0;

    if ((dp = opendir(fullpath)) == NULL){
        return(func(fullpath, &statbuf, FTW_DNR));
    }

    while ((dirp = readdir(dp)) != NULL){
        if (strcmp(dirp->d_name, ".") == 0 | strcmp(dirp->d_name, "..") == 0){
            continue;
        }
        strcpy(&fullpath[n], dirp->d_name);
        if ((ret = dopath(func)) != 0){
            break;
        }
    }

    fullpath[n-1] = 0;

    if (closedir(dp) < 0){
        err_ret("can't close directory %s", fullpath);
    }

    return(ret);
}

static int myfunc(const char *pathname, const struct stat *statptr, int type){
    switch (type){
    case FTW_F:
        switch (statptr->st_mode & S_IFMT){
        case S_IFREG:
            nreg++;
            break;

        case S_IFBLK:
            nblk++;
            break;

        case S_IFCHR:
            nchr++;
            break;

        case S_IFIFO:
            nfifo++;
            break;

        case S_IFLNK:
            nslink++;
            break;

        case S_IFSOCK:
            nsock++;
            break;

        case S_IFDIR:
            err_dump("for S_IFDIR for %s", pathname);
        }
        break;

    case FTW_D:
        ndir++;
        break;

    case FTW_DNR:
        err_ret("can't read directory %s", pathname);
        break;

    case FTW_NS:
        err_ret("stat error for %s", pathname);
        break;

    default:
        err_dump("unknown type %d for pathname %s", type, pathname);
    }

    return(0);
}

================================================
FILE: APUE/4_23.c
================================================
#include "apue.h"

int main(void){
    if (chdir("/tmp") < 0){
        err_sys("chdir failed");
    }

    printf("chdir to /tmp succeeded\n");
    exit(0);
}

================================================
FILE: APUE/4_24.c
================================================
#include "apue.h"

int main(void){
    char *ptr;
    size_t size;

    if (chdir("/usr/spool/uucppublic") < 0){
        err_sys("chdir failed");
    }

    ptr = path_alloc(&size);

    if (getcwd(ptr, size) == NULL){
        err_sys("getcwd failed");
    }

    printf("%s\n", ptr);
    exit(0);
}

================================================
FILE: APUE/4_25.c
================================================
#include "apue.h"
#include <linux/kdev_t.h>

int main(int argc, char *argv[]){
    int i;
    struct stat buf;

    for (i = 1; i < argc; i++){
        printf("%s : ", argv[i]);
        if (stat(argv[i], &buf) < 0){
            err_ret("stat error");
            continue;
        }

        printf("dev = %d/%d\n", MAJOR(buf.st_dev), MINOR(buf.st_dev));
        if (S_ISCHR(buf.st_mode) || S_ISBLK(buf.st_mode)){
            printf("(%s) rdev %d/%d\n", (S_ISCHR(buf.st_mode) ? "character" : "block", MAJOR(buf.st_rdev), MINOR(buf.st_rdev)));
        }
        printf("\n");
    }

    exit(0);
}

================================================
FILE: APUE/4_3.c
================================================
#include "apue.h"

int main(int argc, char* argv[]){
    int i;
    struct stat buf;
    char* ptr;

    for (i = 1; i < argc; i++){
        printf("%s : ", argv[i]);
        if (lstat(argv[i], &buf) < 0){
            err_ret("lstat error");
            continue;
        }

        if (S_ISREG(buf.st_mode)){
            ptr = "regular";
        }
        else if (S_ISDIR(buf.st_mode)){
            ptr = "directory";
        }
        else if (S_ISCHR(buf.st_mode)){
            ptr = "character special";
        }
        else if (S_ISBLK(buf.st_mode)){
            ptr = "block special";
        }
        else if (S_ISFIFO(buf.st_mode)){
            ptr = "fifo";
        }
        else if (S_ISLNK(buf.st_mode)){
            ptr = "symbolic link";
        }
        else if (S_ISSOCK(buf.st_mode)){
            ptr = "socket";
        }
        else {
            ptr = "** unknown mode **";
        }

        printf("%s\n", ptr);
    }

    exit(0);
}

================================================
FILE: APUE/4_8.c
================================================
#include "apue.h"
#include <fcntl.h>

int main(int argc, char* argv[]){
    if (argc != 2){
        err_quit("usage : main <pathname>");
    }

    if (access(argv[1], R_OK) < 0){
        err_ret("access error for %s", argv[1]);
    }
    else{
        printf("read access OK\n");
    }

    if (open(argv[1], O_RDONLY) < 0){
        err_ret("open error for %s", argv[1]);
    }
    else{
        printf("open for reading OK\n");
    }

    exit(0);
}

================================================
FILE: APUE/4_9.c
================================================
#include "apue.h"
#include <fcntl.h>

#define RWRWRW (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)

int main(void){
    umask(0);
    if (creat("foo", RWRWRW) < 0){
        err_sys("creat error for foo");
    }
    umask(S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
    if (creat("bar", RWRWRW) < 0){
        err_sys("creat error for bar");
    }

    exit(0);
}

================================================
FILE: APUE/5_11.c
================================================
#include "apue.h"

void pr_stdio(const char *, FILE *);
int is_unbuffered(FILE *);
int is_linebuffered(FILE *);
int buffer_size(FILE *);

int main(void){
    FILE *fp;

    fputs("enter any character\n", stdout);
    if (getchar() == EOF){
        err_sys("getchar error");
    }

    fputs("one line to standard error\n", stderr);

    pr_stdio("stdin", stdin);
    pr_stdio("stdout", stdout);
    pr_stdio("stderr", stderr);

    if ((fp = fopen("/etc/passwd", "r")) == NULL){
        err_sys("fopen error");
    }

    if (getc(fp) == EOF){
        err_sys("getc error");
    }

    pr_stdio("/etc/passwd", fp);

    exit(0);
}

void pr_stdio(const char *name, FILE *fp){
    printf("stream = %s, ", name);
    if (is_unbuffered(fp)){
        printf("unbuffered");
    }
    else if (is_linebuffered(fp)){
        printf("line buffered");
    }
    else{
        printf("full buffered");
    }

    printf(", buffer size = %d\n", buffer_size(fp));
}

int is_unbuffered(FILE *fp){
    return(fp->_flags & _IONBF);
}

int is_linebuffered(FILE *fp){
    return(fp->_flags & _IOLBF);
}

int buffer_size(FILE *fp){
    return(fp->_IO_buf_end - fp->_IO_buf_base);
}

================================================
FILE: APUE/5_12.c
================================================
#include "apue.h"

int main(void){
    char name[L_tmpnam], line[MAXLINE];
    FILE *fp;

    printf("%s\n", tmpnam(NULL));

    tmpnam(name);
    printf("%s\n", name);

    if ((fp = tmpfile()) == NULL){
        err_sys("tmpfile error");
    }

    fputs("one line of output\n", fp);
    rewind(fp);

    if (fgets(line, sizeof(line), fp) == NULL){
        err_sys("fgets error");
    }

    fputs(line, stdout);
    exit(0);
}

================================================
FILE: APUE/5_13.c
================================================
#include "apue.h"

void make_tmp(char *template);

int main(void){
    char good_template[] = "/tmp/dirXXXXXX";
    char *bad_template = "/tmp/dirXXXXXX";

    printf("trying to create first temp file...\n");
    make_tmp(good_template);
    printf("trying to create second temp file...\n");
    make_tmp(bad_template);

    exit(0);
}

void make_tmp(char *template){
    int fd;
    struct stat statbuf;

    if ((fd = mkstemp(template)) < 0){
        err_sys("mkstemp error");
    }
    printf("temp name = %s\n", template);
    close(fd);

    if (stat(template, &statbuf) < 0){
        if (errno == ENOENT){
            printf("file doesn't exist\n");
        }
        else{
            err_sys("stat error");
        }
    }
    else{
        printf("file exist\n");
        unlink(template);
    }
}

================================================
FILE: APUE/5_15.c
================================================
#include "apue.h"

#define BSZ 48

int main(void){
    FILE *fp;
    char buf[BSZ];

    memset(buf, 'a', BSZ-2);
    buf[BSZ-2] = '\0';
    buf[BSZ-1] = 'X';

    if ((fp = fmemopen(buf, BSZ, "w+")) == NULL){
        err_sys("fmemopen error");
    }

    printf("initial buffer contents : %s\n", buf);
    fprintf(fp, "hello world");
    printf("before flush : %s\n", buf);
    fflush(fp);
    printf("after flush : %s\n", buf);
    printf("length of string in buffer = %ld\n", (long)strlen(buf));


    memset(buf, 'b', BSZ-2);
    buf[BSZ-2] = '\0';
    buf[BSZ-1] = 'X';
    fprintf(fp, "hello world");
    fseek(fp, 0, SEEK_SET);
    printf("after fseek : %s\n", buf);
    printf("length of string in buffer = %ld\n", (long)strlen(buf));



    memset(buf, 'c', BSZ-2);
    buf[BSZ-2] = '\0';
    buf[BSZ-1] = 'X';
    fprintf(fp, "hello world");
    fclose(fp);
    printf("after fclose : %s\n", buf);
    printf("length of string in buffer = %ld\n", (long)strlen(buf));

    return(0);
}

================================================
FILE: APUE/5_4.c
================================================
#include "apue.h"

int main(void){
    int c;

    while ((c = getc(stdin)) != EOF){
        if (putc(c, stdout) == EOF){
            err_sys("output error");
        }
    }

    if (ferror(stdin)){
        err_sys("input error");
    }

    exit(0);
}

================================================
FILE: APUE/5_5.c
================================================
#include "apue.h"

int main(void){
    char buf[MAXLINE];

    while (fgets(buf, MAXLINE, stdin) != NULL){
        if (fputs(buf, stdout) == EOF){
            err_sys("output error");
        }
    }

    if (ferror(stdin)){
        err_sys("input error");
    }

    exit(0);
}

================================================
FILE: APUE/6_11.c
================================================
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void){
    time_t t;
    struct tm *tmp;
    char buf1[16];
    char buf2[64];

    time(&t);
    tmp = localtime(&t);

    if (strftime(buf1, 16, "time and date : %r, %a %b %d, %Y", tmp) == 0){
        printf("buffer length 16 is too small\n");
    }
    else{
        printf("%s\n", buf1);
    }

    if (strftime(buf2, 64, "time and date : %r, %a %b %d, %Y", tmp) == 0){
        printf("buffer length 64 is too small\n");
    }
    else{
        printf("%s\n", buf2);
    }

    exit(0);
}

================================================
FILE: APUE/6_2.c
================================================
#include <pwd.h>
#include <stddef.h>
#include <string.h>

struct passwd *getpwnam(const char *name){
    struct passwd *ptr;
    setpwent();

    while ((ptr = getpwent) != NULL){
        if (strcmp(name, ptr->pw_name) == 0){
            break;
        }
    }

    endpwent();
    return(ptr);
}

================================================
FILE: APUE/7_1.c
================================================
#include <stdio.h>

int main(void){
    printf("hello world\n");
}

================================================
FILE: APUE/7_13.c
================================================
#include "apue.h"
#include <setjmp.h>

static void f1(int, int, int, int);
static void f2(void);

static jmp_buf jmpbuffer;
static int globval;

int main(void){
    int autoval;
    register int regival;
    volatile int volaval;
    static int statval;

    globval = 1;
    autoval = 2;
    regival = 3;
    volaval = 4;
    statval = 5;

    if (setjmp(jmpbuffer) != 0){
        printf("after longjmp : \n");
        printf("globval = %d, autoval = %d, regival = %d, volaval = %d, statval = %d\n",
                globval, autoval, regival, volaval, statval);
        exit(0);
    }

    globval = 95;
    autoval = 96;
    regival = 97;
    volaval = 98;
    statval = 99;

    f1(autoval, regival, volaval, statval);
    exit(0);
}


static void f1(int i, int j, int k, int l){
    printf("in f1() : \n");
    printf("globval = %d, autoval = %d, regival = %d, volaval = %d, statval = %d\n",
                globval, i, j, k, l);
    f2();
}

static void f2(){
    longjmp(jmpbuffer, 1);
}

================================================
FILE: APUE/7_16.c
================================================
#include "apue.h"
#include <sys/resource.h>

#define doit(name) pr_limits(#name, name)

static void pr_limits(char *, int);

int main(void){
#ifdef RLIMIT_AS
    doit(RLIMIT_AS);
#endif

    doit(RLIMIT_CORE);
    doit(RLIMIT_CPU);
    doit(RLIMIT_DATA);
    doit(RLIMIT_FSIZE);

#ifdef RLIMIT_MEMLOCK
    doit(RLIMIT_MEMLOCK);
#endif

#ifdef RLIMIT_MSGQUEUE
    doit(RLIMIT_MSGQUEUE);
#endif

#ifdef RLIMIT_NICE
    doit(RLIMIT_NICE);
#endif

    doit(RLIMIT_NOFILE);

#ifdef RLIMIT_NPROC
    doit(RLIMIT_NPROC);
#endif

#ifdef RLIMIT_NPTS
    doit(RLIMIT_NPTS);
#endif

#ifdef RLIMIT_RSS
    doit(RLIMIT_RSS);
#endif

#ifdef RLIMIT_SBSIZE
    doit(RLIMIT_SBSIZE);
#endif

#ifdef RLIMIT_SIGPENDING
    doit(RLIMIT_SIGPENDING);
#endif

    doit(RLIMIT_STACK);

#ifdef RLIMIT_SWAP
    doit(RLIMIT_SWAP);
#endif

#ifdef RLIMIT_VMEM
    doit(RLIMIT_VMEM);
#endif

    exit(0);
}

static void pr_limits(char *name, int resource){
    struct rlimit limit;
    unsigned long long lim;

    if (getrlimit(resource, &limit) < 0){
        err_sys("getrlimit error");
    }

    printf("%-14s  ", name);

    if (limit.rlim_cur == RLIM_INFINITY){
        printf("(infinity) ");
    }
    else{
        lim = limit.rlim_cur;
        printf("%10lld  ", lim);
    }

    if (limit.rlim_max == RLIM_INFINITY){
        printf("(infinity) ");
    }
    else{
        lim = limit.rlim_max;
        printf("%10lld  ", lim);
    }

    putchar((int)'\n');
}

================================================
FILE: APUE/7_3.c
================================================
#include "apue.h"

static void my_exit1(void);
static void my_exit2(void);

int main(void){
    if (atexit(my_exit2) != 0){
        err_sys("can't register my_exit2");
    }

    if (atexit(my_exit1) != 0){
        err_sys("can't register my_exit1");
    }

    if (atexit(my_exit1) != 0){
        err_sys("can't register my_exit1");
    }

    printf("main is done\n");
    return(0);
}

static void my_exit1(void){
    printf("first exit handler\n");
}

static void my_exit2(void){
    printf("second exit handler\n");
}

================================================
FILE: APUE/7_4.c
================================================
#include "apue.h"

int main(int argc, char *argv[]){
    int i;

    for (i = 0; i < argc; i++){
        printf("argv[%d] : %s\n", i, argv[i]);
    }

    exit(0);
}

================================================
FILE: APUE/8_1.c
================================================
#include "apue.h"

int globvar = 6;
char buf[] = "a write to stdout\n";

int main(void){
    int var;
    pid_t pid;

    var = 88;
    if (write(STDOUT_FILENO, buf, sizeof(buf)-1) != sizeof(buf) - 1){
        err_sys("write error");
    }
    printf("before fork : \n");

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }
    else if (pid == 0){
        globvar++;
        var++;
    }
    else{
        sleep(2);
    }

    printf("pid = %ld, glob = %d, var = %d\n", (long)getpid(), globvar, var);

    exit(0);
}

================================================
FILE: APUE/8_12.c
================================================
#include "apue.h"

static void charactatime(char *);

int main(void){
    pid_t pid;

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }
    else if (pid == 0){
        charactatime("output from child\n");
    }
    else{
        charactatime("output from parent\n");
    }

    exit(0);
}

static void charactatime(char *str){
    char* ptr;
    int c;

    setbuf(stdout, NULL);
    for (ptr = str; (c = *ptr++) != 0;){
        putc(c, stdout);
    }
}

================================================
FILE: APUE/8_3.c
================================================
#include "apue.h"

int globvar = 6;

int main(void){
    int var;
    pid_t pid;

    var = 88;
    printf("before fork : \n");

    if ((pid = vfork()) < 0){
        err_sys("vfork error");
    }
    else if (pid == 0){
        globvar++;
        var++;
        _exit(0);
    }

    printf("pid = %ld, glob = %d, var = %d\n", (long)getpid(), globvar, var);

    exit(0);
}

================================================
FILE: APUE/8_5.c
================================================
#include "apue.h"
#include <sys/wait.h>

void pr_exit(int status){
    if (WIFEXITED(status)){
        printf("normal termination, exit status = %d\n", WEXITSTATUS(status));
    }
    else if (WIFSIGNALED(status)){
        printf("abnormal termination, signal number = %d%s\n", WTERMSIG(status),

#ifdef WCOREDUMP
    WCOREDUMP(status) ? " (core file generated )" : "");
#else
    "");
#endif
    }
    else if (WIFSTOPPED(status)){
        printf("child stopped, signal number = %d\n", WSTOPSIG(status));
    }
}

================================================
FILE: APUE/8_6.c
================================================
#include "apue.h"
#include <sys/wait.h>

void pr_exit(int status);

int main(void){
    pid_t pid;
    int status;

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }
    else if(pid == 0){
        exit(7);
    }

    if (wait(&status) != pid){
        err_sys("wait error");
    }
    pr_exit(status);

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }
    else if(pid == 0){
        abort();
    }

    if (wait(&status) != pid){
        err_sys("wait error");
    }
    pr_exit(status);

    if ((pid = fork()) < 0){
        err_sys("fork error");
    }
    else if(pid == 0){
        status /= 0;
    }

    if (wait(&status) != pid){
        err_sys("wait error");
    }
    pr_exit(status);

    exit(0);
}

void pr_exit(int status){
    if (WIFEXITED(status)){
        printf("normal termination, exit status = %d\n", WEXITSTATUS(status));
    }
    else if (WIFSIGNALED(status)){
        printf("abnormal termination, signal number = %d%s\n", WTERMSIG(status),

#ifdef WCOREDUMP
    WCOREDUMP(status) ? " (core file generated )" : "");
#else
    "");
#endif
    }
    else if (WIFSTOPPED(status)){
        printf("child stopped, signal number = %d\n", WSTOPSIG(status));
    }
}

================================================
FILE: APUE/8_8.c
================================================
#include "apue.h"
#include <sys/wait.h>

int main(void){
    pid_t pid;
    if ((pid = fork()) < 0){
        err_sys("fork error");
    }
    else if (pid == 0){
        if ((pid = fork()) < 0){
            err_sys("fork error");
        }
        else if (pid > 0){
            exit(0);
        }

        sleep(2);
        printf("second child, parent pid = %ld\n", (long)getppid());
        exit(0);
    }

    if (waitpid(pid, NULL, 0) != pid){
        err_sys("waitpid error");
    }

    exit(0);
}

================================================
FILE: APUE/FuncPointer.c
================================================
#include <stdio.h>

typedef int Myfunc(int a, int b);

Myfunc myfunc;

int myftw(int , int , Myfunc *);

int main(void){
    int x = 3;
    int y = 4;
    int ret = myftw(&x, &y, &myfunc);
    printf("%d\n", ret);

    return 0;
}

int myfunc(int a, int b){
    return (a < b);
}

int myftw(int a, int b, Myfunc *func){
    return func(a, b);
}

================================================
FILE: Makefile
================================================
# Find out all the include and source files for
SRC_FILE := $(wildcard *.c)
OBJ_FILE := $(subst .c,.o,$(SRC_FILE))
TARGET := main
CFLAGS := -std=c99

.PHONY: all

all: $(TARGET)

$(TARGET): $(OBJ_FILE)
	$(CC) -o $@ $^
%.o: %.c
	$(CC) -o $@ -c $< $(CFLAGS)

clean:
	rm $(OBJ_FILE) $(TARGET) -f


================================================
FILE: README.md
================================================
# apue
Advanced Programming in the UNIX