The C Library Reference describes the functions and macros
in the Watcom 10.6 C Library.
Use the following links to find a function quickly:
This reference includes the following:
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- This reference doesn't describe the Watcom C graphics routines. You
should use the Photon graphics routines instead.
- The ncurses package is a freeware subroutine library used for
managing input from and output to the screen, independent of the
terminal used. It's described in the online
Miscellaneous
Utilities reference.
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The C library provides much of the power usually associated with the
C language.
Library functions are called as if they had been defined within the
program.
When the program is linked, the code for these routines is incorporated
into the program by the linker.
Strictly speaking, it isn't necessary to declare the library
functions that return int.
However, it's best to declare all functions by including the
header files found in the Synopsis section with each function.
Not only does this declare the return value, but also the type
expected for each of the arguments as well as the number of arguments.
This enables the Watcom C and C++ compilers to check the arguments
coded with each function call.
- New categories of functions:
- An overview of POSIX.4 message queues
- The classification section for each function now indicates whether or
not it's safe to call the function from a signal handler,
interrupt handler, or in a multithreaded program. There's a summary
of this information in the
How's It Safe to Use These Functions?
chapter.
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The functions designated as threadsafe are safe only if you create threads
with _beginthread(), not
tfork(). |
- _beginthread()
- The example has been corrected.
- _bgetcmd()
- This function returns the number of bytes required to store the
command line, excluding the terminating null character.
- _CA_PCI_BIOS_Present()
- This function returns PCI_SUCCESS if PCI BIOS is
present, and -1 if it isn't.
Programs calling the _CA_PCI_... functions must be
linked with privity level 1 (cc option -T1)
and must be run as root.
The stack size must be less than 64K.
- _CA_PCI_Find_Device()
- The example has been corrected.
- clock()
- This function simply returns the difference between the
current time and the time the program started, so it gives incorrect
results if the system time changes somewhere between. The
times() function
provides more useful information.
- dev_read()
- The example has been corrected - there shouldn't be
ampersands (&) in front of buf in the calls to
dev_read() and Receive().
- exec()
- The flags field of the qnx_spawn_options are
effectively ignored when using the exec... functions
because you're not creating a new process.
- fcntl()
- Locks aren't propagated on calls to fork() or the
spawn... functions.
A clearer example has been added.
- fdopen()
- The example has been replaced.
- fnmatch()
- The FNM_NOESCAPE flag has been added and the
description of the FNM_QUOTE flag (a QNX
extension) has been corrected.
- getcmd()
- The cmdname() function has been added to the See Also list.
- getopt()
- This function refers to the POSIX Utility Syntax
Guidelines 1003.2 section 2.10.2, not 2.11.2.
- gets()
- It's better to use
fgets() than
gets().
With gets(), data beyond the array buf
is destroyed if a newline character isn't read from the input stream
stdin before the end of the array buf is reached.
- int386(), int386x(), int86(), and
int86x()
- These functions aren't useful in QNX and have been removed from
this reference.
- ioctl()
- Moved from the TCP/IP Programmer's Guide.
- __iscsym(),
__iscsymf()
- These are macros, not functions.
- lseek()
- The Returns section has been corrected.
- lstat()
- The description of the S_ISLNK() macro has been moved here
from stat() because stat() doesn't return
information about symbolic links.
- mq_notify()
- This function sets errno to ESRCH
if the notification argument is NULL, but
the current process isn't registered for notification.
- mq_send()
- This function returns 0 on success, and -1 if an error occurs.
- popen()
- This function calls spawnlp(), not spawnl().
- print_usage()
- This function doesn't return if successful.
- qnx_hint_attach()
- The synopsis has been corrected.
The example has been modified so that it doesn't use the
check_stack pragma, which doesn't do anything under QNX.
- qnx_ioctl()
- An example has been added.
- qnx_name_locate()
- The description has been corrected.
- qnx_pflags()
- If a process sets the _PPF_PRIORITY_FLOAT flag, the
messages sent to it are ordered as if _PPF_PRIORITY_REC
were set as well.
 |
Don't spawn processes while the _PPF_INFORM flag
is set - your
process and Proc will become Send-blocked.
It's best not to use this flag at all; use a I/O manager (or
resource manager) and watch for _IO_CLOSE messages
from the processes you're interested in.
|
- qnx_proxy_detach()
- This function can detach only proxies attached to your process,
and not proxies created by your process.
- qnx_psinfo()
- Now includes a description of the _psinfo data
structure.
The example in the discussion of the _seginfo structure
has been corrected.
If you ask for information about a process that doesn't exist,
qnx_psinfo() might return information about another
process, but not necessarily the one with the next montonically
greater process ID.
- qnx_scheduler()
- The example has been replaced. The description of adaptive
scheduling (see SCHED_OTHER) has been corrected.
- qnx_segment_alloc()
- Programs that call this function must run as root.
- qnx_spawn()
- The synopsis includes <sys/sched.h>, not
<sched.h>.
If you specify _SPAWN_NOZOMBIE and start a child
on a remote node, qnx_spawn() returns 0, not the child's
process ID.
The value of envp cannot be NULL, but
envp[0] can be a NULL pointer, if no
environment strings are passed.
- qnx_spawn_options
- The ctfd (controlling terminal file descriptor) field
was missing from the data structure and initial values.
- qnx_ticksize
- _TICKSIZE_EXTERNAL has been removed from the
possible flags.
- qnx_vc_poll_parm
- If you wish to change the poll parameters, your program must run
as root.
- raise()
- The synopsis has been corrected.
- scanf()
- The meaning of a dash in a format string (for example,
[0-9]) has been clarified.
- sem_init()
- This function returns 0 if successful.
This function sets errno to EAGAIN, not
ENOSPC, if the limit on semaphores has been reached
or a resource required to initialize the semaphore has been exhausted.
- sem_init(),
sem_post(),
sem_trywait(),
sem_wait()
- The example can be found in the
/usr/demo/src/semaphores directory.
- shm_unlink()
- This function sets errno to EINVAL if
you try to unlink physical memory.
- sigaction()
- This function fails and sets errno to EINVAL
if you try to change the action for SIGKILL or
SIGSTOP.
- signal()
- (QNX extension)
If a process sets the action for the SIGCHLD signal to
SIG_IGN:
- the child exits without creating a zombie process
- no signal is generated for the process when a child process ends
- the process doesn't need to wait() on the child
- stat()
- The _stat() function has been removed because it isn't
implemented for QNX-use stat() instead.
This function can't be used to get information about a symbolic
link; use lstat() instead.
The S_ISLNK() macro isn't useful with stat()
because stat() follows the link and gives information about
the resulting file or directory.
The stat() function returns -1 if the information
couldn't be obtained.
- _strdate()
- Since the year is expressed as two digits, beware of problems with the
year 2000.
- strtoul()
- This function accepts a sign as part of the input string, but
always returns an unsigned long.
- Trace functions
- You must compile with privity level 1 to use these functions,
except under Neutrino.
- ttyname()
- The example has been corrected.
- uname()
- The list of errors has been corrected.
- waitpid()
- The Returns section has been corrected.
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