Function Prototypes

Question 1

memcpy

Answer 1

void *memcpy(void *restrict dst, const void *restrict src, size_t n);

• Copies n bytes from memory area src to memory area dst

Question 2

strcpy

Answer 2

char *stpcpy(char *dst, const char *src);

• Copies string src to dst

Question 3

malloc

Answer 3

void *malloc(size_t size);

• Allocates block of memory and returns pointer

Question 4

calloc

Answer 4

void *calloc(size_t count, size_t size);

• Allocates space for count objects, fills with zero

Question 5

realloc

Answer 5

void *realloc(void *ptr, size_t size);

• Change the size of memory pointed to by ptr to size, returns ptr

Question 6

free

Answer 6

void free(void *ptr);

• Deallocates memory allocation pointed to by ptr

Question 7

strdup

Answer 7

char *strdup(const char *s1);

• Allocates sufficient memory for a copy of the string s1, does the copy, and returns a pointer to it

Question 8

fopen

Answer 8

FILE *fopen(const char *restrict filename, const char *restrict mode);

• Opens file from filename and returns pointer to file stream

Question 9

fdopen

Answer 9

FILE *fdopen(int fildes, const char *mode);

• Opens file from filedes and returns pointer to file stream

Question 10

open

Answer 10

int open(const char *pathname, int flags);

• Open file at pathname for reading/writing, returns file descriptor

Question 11

close

Answer 11

int close(int fildes);

• Close file associated with file destination, returns 0 or -1

Question 12

read

Answer 12

ssize_t read(int fildes, void *buf, size_t nbyte);

• Read nbyte bytes of data from fildes into the buffer pointed to by buf. Returns number of bytes read or -1

Question 13

write

Answer 13

ssize_t write(int fildes, const void *buf, size_t nbyte);

• Write nbyte bytes of data from buffer pointed to by buf into the filedes file. Returns number of bytes written or -1

Question 14

lseek

Answer 14

off_t lseek(int fildes, off_t offset, int whence);

• Repositions the offset of the file descriptor fildes to the argument offset, according to the directive whence.

whence SEEK_SET = set to offset bytes
whence SEEK_CUR = current location plus bytes
whence SEEK_END = size of file plus bytes

Question 15

stat

Answer 15

int stat(const char *path, struct stat *buf);

• Obtains information about the file pointed to by path.

Question 16

fstat

Answer 16

int fstat(int filedes, struct stat *buf);

• Obtains information about file descriptor fildes.

Question 17

lstat

Answer 17

int lstat(const char *path, struct stat *buf);

• Obtains information about the symbolic link

Question 18

opendir

Answer 18

DIR *opendir(const char *name);

• Opens the directory named by filename, associates a directory stream and returns pointer to it

Question 19

readdir

Answer 19

struct dirent *readdir(DIR *dirp);

• Returns a pointer to the next directory entry.

Question 20

getcwd

Answer 20

char *getcwd(char *buf, size_t size);

• Get the current working directory

Question 21

chdir

Answer 21

int chdir(const char *path);

• Change the current working directory to path, returns 0 or -1