Subj : Re: pthreads and othe POSIX APISa
To   : comp.programming.threads
From : loic-dev
Date : Mon Apr 18 2005 04:19 am

Hi Jarek,

> What is the relation between pthreads and other POSIX defined
> system/library calls ? How can I know, wheather a function can
> /cannot be concurrently called from many treads ?
> Is there any guideline for this ?

Yes: the Single Unix Specification (SUS):
http://www.unix.org/version3/online.html

Just register (this is a free and painless process) to access the full
spec.


> Or should I just carefully
> read the man pages about each call I'm going to use
> from within a thread ?

That would have been a good idea to force people to read all the POSIX
standards ;-)

Fortunately, there is a simple rule: all SUS functions are thread-safe,
except a well defined list of functions that are not required to be
thread-safe.

[ Not required to be thread-safe doesn't mean that they are necessarily
unsafe . On a particular implementation, the function might be well
thread-safe. But that's implementation specific: on another
implementation, the same function might be unsafe. Hence, for
portability reasons, don't make any assumption about thread safety for
those functions)

Cheers,
Loic.

The list of functions that are not required to be thread-safe
accordingly to SUSv3:

<copy>

asctime()
basename()
catgets()
crypt()
ctime()
dbm_clearerr()
dbm_close()
dbm_delete()
dbm_error()
dbm_fetch()
dbm_firstkey()
dbm_nextkey()
dbm_open()
dbm_store()
dirname()
dlerror()
drand48()




ecvt()
encrypt()
endgrent()
endpwent()
endutxent()
fcvt()
ftw()
gcvt()
getc_unlocked()
getchar_unlocked()
getdate()
getenv()
getgrent()
getgrgid()
getgrnam()
gethostbyaddr()
gethostbyname()




gethostent()
getlogin()
getnetbyaddr()
getnetbyname()
getnetent()
getopt()
getprotobyname()
getprotobynumber()
getprotoent()
getpwent()
getpwnam()
getpwuid()
getservbyname()
getservbyport()
getservent()
getutxent()
getutxid()




getutxline()
gmtime()
hcreate()
hdestroy()
hsearch()
inet_ntoa()
l64a()
lgamma()
lgammaf()
lgammal()
localeconv()
localtime()
lrand48()
mrand48()
nftw()
nl_langinfo()
ptsname()




putc_unlocked()
putchar_unlocked()
putenv()
pututxline()
rand()
readdir()
setenv()
setgrent()
setkey()
setpwent()
setutxent()
strerror()
strtok()
ttyname()
unsetenv()
wcstombs()
wctomb()

</copy>

.