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  82 ><H1
  83 ><A
  84 NAME="POSIX-STANDARD-SUPPORT">Chapter 31. POSIX Standard Support</H1
  85 ><DIV
  86 CLASS="TOC"
  87 ><DL
  88 ><DT
  89 ><B
  90 >Table of Contents</B
  91 ></DT
  92 ><DT
  93 ><A
  94 HREF="posix-standard-support.html#POSIX-PROCESS-PRIMITIVES"
  95 >Process Primitives &#0091;POSIX Section 3&#0093;</A
  96 ></DT
  97 ><DT
  98 ><A
  99 HREF="posix-process-environment.html"
 100 >Process Environment &#0091;POSIX Section 4&#0093;</A
 101 ></DT
 102 ><DT
 103 ><A
 104 HREF="posix-files-and-directories.html"
 105 >Files and Directories &#0091;POSIX Section 5&#0093;</A
 106 ></DT
 107 ><DT
 108 ><A
 109 HREF="posix-input-and-output.html"
 110 >Input and Output &#0091;POSIX Section 6&#0093;</A
 111 ></DT
 112 ><DT
 113 ><A
 114 HREF="posix-device-and-class-specific-functions.html"
 115 >Device and Class Specific Functions &#0091;POSIX Section 7&#0093;</A
 116 ></DT
 117 ><DT
 118 ><A
 119 HREF="posix-c-language-services.html"
 120 >C Language Services &#0091;POSIX Section 8&#0093;</A
 121 ></DT
 122 ><DT
 123 ><A
 124 HREF="posix-system-databases.html"
 125 >System Databases &#0091;POSIX Section 9&#0093;</A
 126 ></DT
 127 ><DT
 128 ><A
 129 HREF="posix-data-interchange-format.html"
 130 >Data Interchange Format &#0091;POSIX Section 10&#0093;</A
 131 ></DT
 132 ><DT
 133 ><A
 134 HREF="posix-synchronization.html"
 135 >Synchronization &#0091;POSIX Section 11&#0093;</A
 136 ></DT
 137 ><DT
 138 ><A
 139 HREF="posix-memory-management.html"
 140 >Memory Management &#0091;POSIX Section 12&#0093;</A
 141 ></DT
 142 ><DT
 143 ><A
 144 HREF="posix-execution-scheduling.html"
 145 >Execution Scheduling &#0091;POSIX Section 13&#0093;</A
 146 ></DT
 147 ><DT
 148 ><A
 149 HREF="posix-clocks-and-timers.html"
 150 >Clocks and Timers &#0091;POSIX Section 14&#0093;</A
 151 ></DT
 152 ><DT
 153 ><A
 154 HREF="posix-message-passing.html"
 155 >Message Passing &#0091;POSIX Section 15&#0093;</A
 156 ></DT
 157 ><DT
 158 ><A
 159 HREF="posix-thread-management.html"
 160 >Thread Management &#0091;POSIX Section 16&#0093;</A
 161 ></DT
 162 ><DT
 163 ><A
 164 HREF="posix-thread-specific-data.html"
 165 >Thread-Specific Data &#0091;POSIX Section 17&#0093;</A
 166 ></DT
 167 ><DT
 168 ><A
 169 HREF="posix-thread-cancellation.html"
 170 >Thread Cancellation &#0091;POSIX Section 18&#0093;</A
 171 ></DT
 172 ><DT
 173 ><A
 174 HREF="posix-non-posix-functions.html"
 175 >Non-POSIX Functions</A
 176 ></DT
 177 ></DL
 178 ></DIV
 179 ><P
 180 >      eCos contains support for the POSIX Specification (ISO&#0047;IEC
 181       9945-1)&#0091;POSIX&#0093;.
 182     </P
 183 ><P
 184 >      POSIX support is divided between the POSIX and the FILEIO
 185       packages. The POSIX package provides support for threads,
 186       signals, synchronization, timers and message queues. The FILEIO
 187       package provides support for file and device I&#0047;O. The two
 188       packages may be used together or separately, depending on
 189       configuration.
 190     </P
 191 ><P
 192 >      This document takes a functional approach to the POSIX
 193       library. Support for a function implies that the data types and
 194       definitions necessary to support that function, and the objects
 195       it manipulates, are also defined. Any exceptions to this are
 196       noted, and unless otherwise noted, implemented functions behave
 197       as specified in the POSIX standard.
 198     </P
 199 ><P
 200 >      This document only covers the differences between the eCos
 201       implementation and the standard; it does not provide complete
 202       documentation. For full information, see the POSIX standard
 203       &#0091;POSIX&#0093;. Online, the Open Group Single Unix
 204       Specification &#0091;SUS2&#0093; provides complete documentation
 205       of a superset of POSIX. If you have access to a Unix system with
 206       POSIX compatibility, then the manual pages for this will be of
 207       use.  There are also a number of books available.
 208       &#0091;Lewine&#0093; covers the process, signal, file and I&#0047;O
 209       functions, while &#0091;Lewis1&#0093;, &#0091;Lewis2&#0093;,
 210       &#0091;Nichols&#0093; and &#0091;Norton&#0093; cover Pthreads and
 211       related topics (see Bibliography, xref). However, many of these
 212       books are oriented toward using POSIX in non-embedded systems,
 213       so care should be taken in applying them to programming under
 214       eCos.
 215     </P
 216 ><P
 217 >      The remainder of this chapter broadly follows the structure
 218       of the POSIX Specification. References to the appropriate
 219       section of the Standard are included.
 220     </P
 221 ><P
 222 >      Omitted functions marked with &#8220;&#0047;&#0047; TBA&#8221;
 223       are potential candidates for later implementation.
 224     </P
 225 ><DIV
 226 CLASS="SECT1"
 227 ><H1
 228 CLASS="SECT1"
 229 ><A
 230 NAME="POSIX-PROCESS-PRIMITIVES">Process Primitives &#0091;POSIX Section 3&#0093;</H1
 231 ><DIV
 232 CLASS="SECT2"
 233 ><H2
 234 CLASS="SECT2"
 235 ><A
 236 NAME="AEN12979">Functions Implemented</H2
 237 ><TABLE
 238 BORDER="5"
 239 BGCOLOR="#E0E0F0"
 240 WIDTH="70%"
 241 ><TR
 242 ><TD
 243 ><PRE
 244 CLASS="SCREEN"
 245 >int kill(pid&#0095;t pid, int sig);
 246 int pthread&#0095;kill(pthread&#0095;t thread, int sig);
 247 int sigaction(int sig, const struct sigaction &#0042;act,
 248               struct sigaction &#0042;oact);
 249 int sigqueue(pid&#0095;t pid, int sig, const union sigval value);
 250 int sigprocmask(int how, const sigset&#0095;t &#0042;set,
 251                 sigset&#0095;t &#0042;oset);
 252 int pthread&#0095;sigmask(int how, const sigset&#0095;t &#0042;set,
 253                     sigset&#0095;t &#0042;oset);
 254 int sigpending(sigset&#0095;t &#0042;set);
 255 int sigsuspend(const sigset&#0095;t &#0042;set);
 256 int sigwait(const sigset&#0095;t &#0042;set, int &#0042;sig);
 257 int sigwaitinfo(const sigset&#0095;t &#0042;set, siginfo&#0095;t &#0042;info);
 258 int sigtimedwait(const sigset&#0095;t &#0042;set, siginfo&#0095;t &#0042;info,
 259                  const struct timespec &#0042;timeout);
 260 int sigemptyset(sigset&#0095;t &#0042;set);
 261 int sigfillset(sigset&#0095;t &#0042;set);
 262 int sigaddset(sigset&#0095;t &#0042;set, int signo);
 263 int sigdelset(sigset&#0095;t &#0042;set, int signo);
 264 int sigismember(const sigset&#0095;t &#0042;set, int signo);
 265 unsigned int alarm( unsigned int seconds );
 266 int pause( void );
 267 unsigned int sleep( unsigned int seconds );</PRE
 268 ></TD
 269 ></TR
 270 ></TABLE
 271 ></DIV
 272 ><DIV
 273 CLASS="SECT2"
 274 ><H2
 275 CLASS="SECT2"
 276 ><A
 277 NAME="AEN12982">Functions Omitted</H2
 278 ><TABLE
 279 BORDER="5"
 280 BGCOLOR="#E0E0F0"
 281 WIDTH="70%"
 282 ><TR
 283 ><TD
 284 ><PRE
 285 CLASS="SCREEN"
 286 >pid&#0095;t fork(void);
 287 int execl( const char &#0042;path, const char &#0042;arg, ... );
 288 int execv( const char &#0042;path, char &#0042;const argv&#0091;&#0093; );
 289 int execle( const char &#0042;path, const char &#0042;arg, ... );
 290 int execve( const char &#0042;path, char &#0042;const argv&#0091;&#0093;,
 291             char &#0042;const envp&#0091;&#0093; );
 292 int execlp( const char &#0042;path, const char &#0042;arg, ... );
 293 int execvp( const char &#0042;path, char &#0042;const argv&#0091;&#0093; );
 294 int pthread&#0095;atfork( void(&#0042;prepare)(void),
 295                     void (&#0042;parent)(void),
 296                     void (&#0042;child)() );
 297 pid&#0095;t wait( int &#0042;stat&#0095;loc );
 298 pid&#0095;t waitpid( pid&#0095;t pid, int &#0042;stat&#0095;loc,
 299                int options );
 300 void &#0095;exit( int status );</PRE
 301 ></TD
 302 ></TR
 303 ></TABLE
 304 ></DIV
 305 ><DIV
 306 CLASS="SECT2"
 307 ><H2
 308 CLASS="SECT2"
 309 ><A
 310 NAME="AEN12985">Notes</H2
 311 ><P
 312 ></P
 313 ><UL
 314 ><LI
 315 ><P
 316 >    Signal handling may be enabled or disabled with the
 317     CYGPKG&#0095;POSIX&#0095;SIGNALS option. Since signals are used
 318     by other POSIX components, such as timers, disabling signals will
 319     disable those components too.
 320     </P
 321 ></LI
 322 ><LI
 323 ><P
 324 >    <SPAN
 325 CLASS="emphasis"
 326 ><I
 327 CLASS="EMPHASIS"
 328 >kill()</I
 329 ></SPAN
 330 > and
 331     <SPAN
 332 CLASS="emphasis"
 333 ><I
 334 CLASS="EMPHASIS"
 335 >sigqueue()</I
 336 ></SPAN
 337 > may only take a
 338     <SPAN
 339 CLASS="strong"
 340 ><B
 341 CLASS="EMPHASIS"
 342 >pid</B
 343 ></SPAN
 344 > argument of zero,
 345     which maps to the current process.
 346     </P
 347 ></LI
 348 ><LI
 349 ><P
 350 >    The <SPAN
 351 CLASS="emphasis"
 352 ><I
 353 CLASS="EMPHASIS"
 354 >SIGEV&#0095;THREAD</I
 355 ></SPAN
 356 > notification type is
 357             not currently implemented.
 358     </P
 359 ></LI
 360 ><LI
 361 ><P
 362 >    Job Control and Memory Protection signals are
 363             not supported.
 364     </P
 365 ></LI
 366 ><LI
 367 ><P
 368 >    An extra implementation defined
 369     <SPAN
 370 CLASS="emphasis"
 371 ><I
 372 CLASS="EMPHASIS"
 373 >si&#0095;code</I
 374 ></SPAN
 375 > value,
 376     <SPAN
 377 CLASS="emphasis"
 378 ><I
 379 CLASS="EMPHASIS"
 380 >SI&#0095;EXCEPT</I
 381 ></SPAN
 382 >, is defined to
 383     distinguish hardware generated exceptions from
 384     others.
 385     </P
 386 ></LI
 387 ><LI
 388 ><P
 389 >    Extra signals are defined:
 390     &#0095;SIGTRAP&#0095;,&#0095;SIGIOT&#0095;,
 391     &#0095;SIGEMT&#0095;, and &#0095;SIGSYS&#0095;. These are
 392     largely to maintain compatibility with the signal numbers used by
 393     GDB.
 394     </P
 395 ></LI
 396 ><LI
 397 ><P
 398 >    Signal delivery may currently occur at unexpected places in some
 399     API functions. Using <SPAN
 400 CLASS="emphasis"
 401 ><I
 402 CLASS="EMPHASIS"
 403 >longjmp()</I
 404 ></SPAN
 405 > to transfer
 406     control out of a signal handler may result in the interrupted
 407     function not being able to complete properly. This may result in
 408     later function calls failing or deadlocking.
 409     </P
 410 ></LI
 411 ></UL
 412 ></DIV
 413 ></DIV
 414 ></DIV
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