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<!DOCTYPE html>
<html dir="ltr" lang="en">
<head>
<meta charset='utf-8'>
<title>Libraries</title>
</head>
<body>
<a href="../index.html">Development Index</a>
<h1>Libraries</h1>
<h2 id="basic">Basic</h2>
<dl>
<dt>include <unistd.h></dt>
<dd>fork, pipe and I/O primitives (read, write, close, etc.)
+ primitve types like uid_t, pid_t etc</dd>
<dt>#include <stdlib.h></dt>
<dd>Standard lib, contains primitves for number conversion
and memory allocation</dd>
<dt>#include <stdio.h></dt>
<dd>Basic i/o lib: printf etc</dd>
<dd>glibc</dd>
<dt>#include <string.h></dt>
<dd>String manipulations</dd>
<dd>glibc</dd>
<dt>#include <time.h></dt>
<dd>Time related functions</dd>
<dd>glibc</dd>
<dt>#include <signal.h></dt>
<dd>Signal handling</dd>
<dd>glibc</dd>
<dt>#include <stdbool.h></dt>
<dd>Boolean type</dd>
<dd>glibc</dd>
<dt>#include <math.h></dt>
<dd>Math functions</dd>
<dd>glibc</dd>
</dl>
<h2 id="advanced">Advanced</h2>
<dl>
<dt>#include <sys/socket.h></dt>
<dd>Socket connections</dd>
<dd>glibc</dd>
<dt>#include <sys/types.h></dt>
<dd>Primitive types like uid_t, pid_t etc</dd>
<dd>glibc</dd>
<dt>#include <netinet/in.h></dt>
<dd> internet address family</dd>
<dd>glibc</dd>
<dt>#include <arpa/inet.h></dt>
<dd> definitions for internet operations</dd>
<dd>glibc</dd>
<dt>#include <pthread.h></dt>
<dd> threads</dd>
<dd>glibc</dd>
<dt>#include <stdatomic.h></dt>
<dd> mutual exclusion locks</dd>
<dd>gcc</dd>
</dl>
<h2 id="random-numbers">Random Numbers</h2>
<pre>
// seed with current time:
// time_t t;
// srand(time(&t));
void srand(unsigned seed);
int rand(void);
</pre>
<h2 id="signals">Signals</h2>
<pre>
sig_t signal(int sig, sig_t func);
int raise(int sig);
int kill(pid_t pid, int sig);
</pre>
<h2 id="sorting">Sorting</h2>
<pre>
void qsort(void* values, size_t num_items, size_t item_size, int (*comparefunc)(const void*, const void*));
</pre>
<h2 id="strings">Strings</h2>
<pre>
// SUCCESS: pointer to destination string
char *strcpy(char *dest, const char *src);
// result == 0 -> strings are equal
// result < 0 -> str1 less than str2
// result > 0 -> str2 less than str1
int strcmp(const char *str1, const char *str2);;
// result == NULL -> no tokens left to retrieve
// else: pointer to last token found
char *strtok(char *str, const char *delim);
// NULL if no match
// else: pointer to first occurence in string
char *strstr(const char *string, const char *substring);
// ERROR: result == 0
int atoi(const char *str);
</pre>
<h2 id="inter-process-communication">Inter Process Communication</h2>
<pre>
// ERROR: result < 0
// result = 0 inside child
// result > 0 inside parent
pid_t fork(void);
// ERROR: result < 0
// SUCCESS: result == 0
int pipe(int fd[2]);
</pre>
<h2 id="file-io">File IO</h2>
<h3>File Modes</h3>
<pre>
mode Description
"r" Opens a file for reading. The file must exist.
"w" Creates an empty file for writing. If a file with the same name already exists, its content is erased and the file is considered as a new empty file.
"a" Appends to a file. Writing operations, append data at the end of the file. The file is created if it does not exist.
"r" Opens a file to update both reading and writing. The file must exist.
"w" Creates an empty file for both reading and writing.
"a" Opens a file for reading and appending.
</pre>
<pre>
// ERROR: result == NULL (also when EOF is reached)
char *fgets(char *str, int strlen, FILE *stream);
// ERROR: result == NULL
FILE *fopen(const char *filename, const char *mode);
// result == EOF when finished reading the stream
// SUCCESS: number of matched items on success
int fscanf(FILE *stream, const char *format, ...);
// ERROR: result == EOF
// SUCCESS: result == 0
int fclose(FILE *stream);
// ERROR: result == -1
// SUCCESS: number of bytes written
ssize_t write(int fildes, const void *buf, size_t nbyte);
// ERROR: result == -1
// EOF when finished reading
// SUCCESS: number of bytes read
ssize_t read(int fildes, void *buf, size_t nbyte);
// SUCCESS: result > 0
// ERROR: result == EOF
int fputs(const char *restrict s, FILE *restrict stream);
</pre>
<h2 id="shared-memory">Shared Memory</h2>
<pre>
// ERROR: result < 0
// SUCCESS: result == shmid
int shmget(key_t key, size_t size, int shmflg);
// ERROR: result == NULL
void *shmat(int shmid, const void *shmaddr, int shmflg);
// ERROR: result < 0
// SUCCESS: result == 0
int shmdt(const void *shmaddr);
</pre>
<h2 id="networking">Networking</h2>
<pre>
$ pkginfo -o socket.h
</pre>
<pre>
#include "<sys/socket.h>"
</pre>
<pre>
// ERROR: result == -1
// example: sock = socket(AF_INET, SOCK_STREAM, 0);
int socket(int domain, int type, int protocol);
// sockaddr_in struct (man ip 4)
struct sockaddr_in server;
server.sin_family = PF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons(8080);
// ERROR: result < 0
// SUCCESS: result == 0
// example: bind(sock, (struct sockaddr *) &server, sizeof(server))
int bind(int sockfd, const struct sockaddr *my_addr, socklen_t addrlen);
// ERROR: result < 0
// SUCCESS: filedeskriptor for accepted socket
// example: fd = accept(sock, (struct sockaddr *) &client, &client_len);
int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
// SUCCESS: result == 0
// ERROR: result == -1
int listen(int socket, int backlog);
</pre>
<h2 id="threads">Threads</h2>
<pre>
// ERROR: result > 0
// SUCCESS: res == 0
// example: pthread_create(&threads[t], NULL, printHello, (void*)t);
int pthread_create(pthread_t *restrict thread, const pthread_attr_t *restrict attr, void *(*start_routine)(void *), void *restrict arg);
// SUCCESS: result == 0
// ERROR: result > 0
int pthread_join(pthread_t tid, void **ret);
void pthread_exit(void *value_ptr);
</pre>
<a href="../index.html">Development Index</a>
<p>
This is part of the Hive System Documentation.
Copyright (C) 2018
Hive Team.
See the file <a href="../../fdl-1.3-standalone.html">Gnu Free Documentation License</a>
for copying conditions.</p>
</body>
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