Library Routines (libc)

For multi-threaded applications, a thread-specific errno is implemented. Multi-threaded applications must import the errno definition from <errno.h> and compile all components of the application with -D_REENTRANT. The practice of declaring errno as extern int errno; is obsoleted.

errno is no longer a legal name for a structure member in a file that includes <errno.h> and is compiled with -D_REENTRANT. For example, the following

       #include <errno.h>
 
       struct foo {
        int errno ;
        };
       

will not compile with -D_REENTRANT. The solution is to change erno to errnum.

The changes to h_errno and getdate_err are similar to the errno changes.

The function prototype of asctime_r() has changed from

    int asctime_r(const struct tm *, char *, int);

to

    char *asctime_r(const struct tm *, char *);

for conformance with POSIX.1C.

The function prototype of ctime_r() has changed from

    int ctime_r(const time_t *, char *, int);

to

    char *ctime_r(const time_t *, char *);

for conformance with POSIX.1C.

The function prototype of getgrgid_r() has changed from

    int getgrgid_r(gid_t, struct group *, char *, int);

to

    int getgrgid_r(gid_t, struct group *, char *, size_t, struct group**);

for conformance with POSIX.1C.

The function prototype of getgrnam_r() has changed from

    int getgrnam_r(const char *, struct group *, char *, int);

to

    int getgrnam_r(const char *,struct group *,char *, size_t, struct group**);

for conformance with POSIX.1C.

The function prototype of getlogin_r() has changed from

    int getlogin_r (char *, int);

to

    int getlogin_r (char *, size_t);

for conformance with POSIX.1C.

The function prototype of getpwuid_r() has changed from

int getpwuid_r(uid_t, struct passwd *, char *, int);

to

int getpwuid_r(uid_t, struct passwd *, char *, size_t, struct passwd **);

for conformance with POSIX.1C.

The function prototype of getpwnam_r() has changed from

    int getpwnam_r(const char *, struct passwd *, char *, int);

to

    int getpwnam_r(const char *,struct passwd *,char *,size_t,struct passwd **);

for conformance with POSIX.1C.

The function prototype of gmtime_r() has changed from

    int gmtime_r(const time_t *, struct tm *);

to

    struct tm *gmtime_r(const time_t *, struct tm *);

for conformance with POSIX.1C.

The function prototype of localtime_r() has changed from

    int localtime_r(const time_t *, struct tm *);

to

    struct tm *localtime_r(const time_t *, struct tm *);

for conformance with POSIX.1C.

The function prototype of readdir_r() has changed from

    int readdir_r(DIR *, struct dirent *);

to

    int readdir_r(DIR *, struct dirent *,struct dirent **);

for conformance with POSIX.1C.

The function prototype of ttyname_r() has changed from

    int ttyname_r (int, char *, int);

to

    int ttyname_r (int, char *, size_t);

for conformance with POSIX.1C.

The function prototype of rand_r() has changed from

    int rand_r(long *, int *);

to

    int rand_r(unsigned int *);

for conformance with POSIX.1C.

For 10.30, code is added to bypass the nsswitch engine to force calls to local protected password database. The intent is to bypass NIS+.

If NISPLUS_COMSEC is not defined, map_ids.c functions as before.

There is added support for NIS+; modprpw.c now uses private routines from libsec.

There are two new command line switches added:

When adding a user, the system displays a random password of 8 characters instead of an admin number (for example, modprpw -A uid=uid user.

The admin number is not supported.

If built without NISPLUS_COMSEC defined, modprpw behaves as before.

The multibyte routines have been corrected for several Asian locales.

The multibyte routines (mblen(), mbtowc(), mbstowcs(), wctomb(), and wcstombs()) in past releases have incorrectly identified certain invalid characters as valid for the ko_KR.eucKR, zh_CN.hp15CN, zh_TW.big5, and zh_TW.ccdc locales.

The locale definitions and method libraries have been modified so that these locales only recognize 7-bit ASCII single-byte values and the following two-byte values as valid characters:

Locale  First byte         Second byte
- -        -
ko_KR.eucKR     0xa1-0xfe          0xa1-0xfe
 
zh_CN.hp15CN*   0xa1-0xfe          0xa1-0xfe
                0xfb               0x3f-0x7e
                0xfc-0xfe          0x21-0x7e
 
zh_TW.ccdc      0xa1-0xfe          0x21-0x7e,0xa1-0xfe
 
zh_TW.big5      0x81-0xfe          0x40-0x7e,0xa1-0xfe

	NOTE: * The Simplified Chinese locale is no longer supported by the HP15 method library due to the unsymetrical nature of the UDC area. A new method library, libhp15CN.sl, has been created to support the zh_CN.hp15CN locale. To access this library, the -m option of localedef must be used with a method file that specifies the libhp15CN.sl library. See /usr/lib/nls/loc/src/zh_CN.hp15CN.m for an example.

The multibyte.3c routines will now exhibit the behaviour that is documented in the manpage. As the input methods for these languages do not support the invalid characters, this should not impact customer applications. Customers will now be able to use the multibyte routines to check for character validity.

There should be limited impact on performance in most cases. The simplified Chinese locale (zh_CN.hp15CN) user-defined character range ([0xfb,0x3f-0x7e] and [0xfc-0xfe,0x21-0x7e]) requires additional checks that will cause the routines to be slower for UDCs than the other character ranges.

No applications conforming to the documented behaviour will be affected. HP has made every attempt to verify that no applications depend on the prior behaviour.

The ability exists to create and use user-defined locales and method libraries use instead of the system-provided locales.

New interfaces for POSIX.1c support.

A new system call for transmitting the contents of a file across a socket connection. It can be used only when the socket is in a connected state.

These are new interfaces that provide sprintf() type of functionality without overflowing target buffers. The use of these interfaces is recommended in situations where buffer overflows may lead to a security breach.

basename() and dirname() are now safe for usage in multi-threaded applications. In a multi-threaded application, basename() or dirname() will behave as described below:

There is no change in behavior for non-threaded applications. See the manpage for a detailed example on how to correctly use these interfaces.

The value of the symbolic constant HUGE_VAL (defined in <math.h>) is changing to IEEE infinity. The interfaces atof(), strtod(), and wcstod() return HUGE_VAL under certain error conditions; these interfaces will return the new HUGE_VAL value starting with HPUX 10.30.

The printf(3C) family of C library routines will convert the special floating point values for infinity and not a number (NaN) as follows:

The scanf(3C) family of C library routines will add support for converting symbolic representations of infinity and NaN to their floating point representations:

The strtod(3C) and atof(3C) C library routines will add support for converting symbolic representations of infinity and NaN to their floating point representations as follows:

The wcstod(3C) C library routine will add support for converting symbolic representations of infinity and NaN to their floating point representations analogously to the description for strtod(3C) above, namely:

Customers who do not enable floating point exceptions (by default floating point exceptions are not enabled) and use comparison with DBL_MAX will be broken when floating point overflow occurs.

For example the value 1.0e10000 previously would have been converted by strtod() or scanf() to DBL_MAX (a finite representable double precision number). It will now be converted to the IEEE representation for double precision floating point infinity.

The getcwd(3C) interface has been changed to opportunistically pick up the current path prefix from the /etc/mnttab file. In earlier releases, getcwd() used to scan the complete path until / and do stat for almost all the entries in the directories encountered. Now if the scan crosses a mount point, it picks up the rest of the path from the /etc/mnttab file, possibly saving a considerable amount of time.

If any file system is mounted using a symbolic path, getcwd(3C) will return the current working directory including the symbolic mount point. Because the command pwd (/usr/bin/pwd) calls getcwd(3C) to print the working directory, it will also show a similar change in behavior.

If the current path does not cross any symbolic mount point, the getcwd(3C) behavior will be identical to the behavior in HPUX 10.20.

Depending upon variables, such as the number of NFS mounts, local mounts, number of entries in a directory and number of directories the current path have, a substantial performance improvement may result.

If the original path is symbolically linked to the current path, getcwd(3C) can be made to return the original path provided the mount command was issued with original path. In other words, if you want the getcwd(3C) to return the actual path (not the symbolic one), make sure you issue the mount command with the actual path.

The strptime(3c) routine now returns a null pointer for dates not representable by a time_t data type.

The strptime(3c) and getdate(3c) APIs are affected by the changes for the year 2000 rollover. Refer to the section "Support for Dates Beyond the Year 2000" in this document in Chapter 2 for details of the specific changes

Return values on error are now provided in stdlib.h as: _LDBL_MAX, _LDBL_NMAX, and _ZERO.

frexp(), ldexp(), and modf() have been moved to the math library. Applications and libraries that reference these interfaces will now have to include -lm to link with these interfaces.

This feature is to enable an application to identify the version of libc in use. The format of the value returned is as follows:

XXyyZZZZqNL

where

The perror(), strerror(), regex(), regerror(), and getopt() APIs are changed to support XPG4 messaging. A language-dependent message catalog returns error messages by these APIs. The environment variable NLSPATH searches this message catalog. If NLSPATH does not exist in the environment or if the message catalog cannot be found in any of the components specified by NLSPATH, an implementation-dependent default path is used. This default is affected by the setting of LC_MESSAGES.

setlocale() in the 10.30 libc will load locales and methods from /usr/lib/nls/loc/locales.2 and /usr/lib/nls/loc/methods.2, respectively.

iconv_open() in the 10.30 libc will load codeset conversion methods from /usr/lib/nls/iconv/methods.2.

Developers of customized locales, methods and codeset conversion methods will need to deliver these libraries in the new locations described above if they are intended for use in applications built on 10.30.

Developers of customized locales, methods and codeset conversion methods will also need to deliver these libraries in the old locations (methods.1 and locales.1 directories) if they are intended for use in applications built on on prior releases.

Note that the use of setlocale() in applications linked with the archive version of libc is not recommended because it does not guarantee binary compatibility.

Internationalized applications using setlocale() that link with the archive version of libc will not work correctly unless they are built with the compiler option -Wl,-E. Refer to the section on localedef(1M) for details on building such applications.

No impact.

Fully shared bound applications built on prior HPUX releases will not be impacted by the libc changes in HPUX 10.30, provided none of the third party libraries that are used by the application are rebuilt on 10.30.

If you are an application provider that relies on third-party libraries, see the section "Impact of libc Changes on Libraries" that describes the impact.

For applications that do a full rebuild, there is an impact on source compatibility in the APIs affected by the libnsl and Dynamic Name Service Switch related changes.

For details on the source compatibility impact, see the relevant section in this document.

Applications using APIs that will move to libd4r and libnsl need to make makefile changes to link with the new libraries.

Suppose your application:

Such applications are not guaranteed to work correctly for 10.30. For example, multi-threaded DCE applications that linked with archived libc and shared libdce on an earlier release will not run on HP-UX 10.30.

Applications that use these calls might have to change their source code to accommodate behavior changes. Refer to the section "Support for Dates Beyond the Year 2000" in this document in Chapter 2 for details of the specific changes.

	NOTE: This feature impacts thread-safe library providers only.

In traditional non-threaded applications on HP-UX, errno is a global integer. This traditional errno behavior works correctly in user space (DCE) multi-threaded applications because threads are managed in the user space and errno is a part of the context of an individual thread.

In HP-UX 10.30, with the introduction of 1x1 kernel threads, thread management is done within the kernel and therefore errno has to be managed on a per-thread basis.

The per-thread errno is implemented by mapping the symbol errno to an expression that is a modifiable lvalue managed on a per-thread basis when an application compiles with -D_REENTRANT.

How the thread-specific errno works:

This change has the following implications:

To align with the POSIX.1c standard, the function prototypes of the following twelve libc APIs have been changed in HP-UX 10.30. The HP-UX 10.20 versions of these interfaces move to libd4r.

    asctime_r()
    ctime_r()
    getgrnam_r()
    getgrgid_r()
    getlogin_r()
    getpwnam_r()
    getpwuid_r()
    gmtime_r()
    localtime_r()
    rand_r()
    readdir_r()
    ttyname_r()
    

Shared libraries that rely on these APIs and that have a need to continue supporting applications built on older HP-UX releases may have to version.

At 10.30, The RPC and YP APIs are moved to libnsl. The obsoleted HP-UX proprietary _r and _unlocked are moved to libd4r. Refer to the relevant sections in this section for specific details.

This change has the following implications for library providers: library providers either have to establish explicit dependencies on these libraries, or notify end users to also link one or both of these libraries for the application to link successfully.

A shared library can be built by explicitly specifying on the command line the list of libraries that it depends on.

If a shared library has been built with -lc on its ld command line on HPUX 10.30, it has an explicit dependency on libc.2. If an attempt is made to use this library in an application built on a prior release (which is linked with libc.1), the application will be implicitly linking with both libc.1 and libc.2.

Thus, if a shared library is being built with -lc on its ld command line, it can either be used exclusively with applications built on HP-UX 10.30 (if it is rebuilt on HP-UX 10.30), or it can be used exclusively with applications built on older releases (if it is not rebuilt on HP-UX 10.30).

The recommended actions for impacted libraries are:

The value of the constant HUGE_VAL defined in <math.h> has changed to IEEE Infinity in 10.30. atof(), wcstod(), and strtod() return the value of HUGE_VAL under certain error conditions.

Libraries that rely on comparing the return values of atof(), wcstod(), and strtod() with HUGE_VAL will need to version in 10.30.

Routine         Change
===========================================================
 
 
catopen         New NL_CAT_LOCALE processing.
iconv*          New iconv(), iconv_open(), iconv_close()
                functions.
nl_langinfo     New ALT_DIGITS, ERA, ERA_D_T_FMT, ERA_T_FMT
                processing.
printf          New grouping specifier functionality (') to
                printf() family of functions.
strfmon         New strfmon() function, and new header
                file monetary.h.
strptime        New strptime() function.

For more information, see the "New Behavior in Replacement Routines", "iconv", and "XPG4 Conformance" sections in the README for NLS in 10.01.

Routine         Change
===========================================================
 
y0/y1/yn        Bug fix: y0(0.0), y1(0.0), yn(3.0,0.0)
                now return HUGE_VAL.
log/log10       Bug fix: log(0.0), log10(0.0) now return
                ERANGE.

See “Math Library Routines (libm, libM) ” later in this chapter for more information.

Routine         Change
===========================================================
 
glob.h          Added new GLOB_NOSYS #define.
iconv.h         Added new function prototypes for iconv(),
                iconv_open() and iconv_close().
langinfo.h      Added new ALT_DIGITS, ERA, ERA_D_T_FMT,
                ERA_T_FMT #defines.
                Corrected _NL_ITEM_MAX #define.
monetary.h      New header file
nl_types.h      Added new NL_CAT_LOCALE #define.
                Added new strord() function prototype.
regex.h         Added new REG_ENOSYS #define.
wchar.h         Corrected wcschr(), wcsrchr() and wcwidth()
                prototypes.
wordexp.h       Added new WRDE_NOSYS #define.
sys/fcntl.h     Cloned definitions of S_ISUID and S_ISGID
                from sys/stat.h.
sys/ipc.h       Added definition of mode_t; used it for
                struct ipc member "mode".  Hid struct ipc
                members "ndx" and "wait" with __
                (except in _KERNEL).
sys/msg.h       Added definitions of msgqnum_t and msglen_t.
                Used msgqnum_t for msg_qnum, and msglen_t
                for msg_qbytes and  msg_ts.  Corrected ANSI
                prototypes of msgrcv() and msgsnd()to match
                manpage.
sys/shm.h       Added definition of shmatt_t.
                Used shmatt_t for struct msg members
                "shm_nattch" and "shm_cnattch".
                Corrected ANSI prototype of shmget() to
                match manpage.
sys/stat.h      Protected S_ISUID and S_ISGID against
                redefinition.
sys/time.h      Added ANSI prototype and external
                declaration of strptime().

Certain additional changes to HP-UX commands were made for consistency with XPG4 specifications. These changes affect all the utilities in the HP-UX CMDS-MIN fileset. They support the use of the LC_MESSAGES environment variable for selecting localized message catalogs. HP will make similar changes to other commands in a future release to provide a completely consistent messaging environment.

These routines have been added to conform to the SVR4 specification. They provide programmatic access to a standard locking mechanism for controlling access to the /etc/passwd file. Any program that modifies /etc/passwd should be modified to call these routines.

lckpwdf locks /etc/passwd; ulckpwdf unlocks it.

See also “Commercial Security ”.

In each case that required an interface change, HP is delivering a new, thread-safe routine alongside the existing, non-threaded routine. The name of the thread-safe version is the name of the existing routine plus the suffix _r; for example, the thread-safe version of acltostr is acltostr_r.

New, thread-safe routines in libc are:

acltostr_r           getlogin_r              nrand48_r
asctime_r            getmntent_r             ptsname_r
crypt_r              getnetbyaddr_r          pututline_r
ctime_r              getnetbyname_r          rand_r
drand48_r            getnetent_r             readdir_r
ecvt_r               getprotobyname_r        seed48_r
encrypt_r            getprotobynumber_r      setgrent_r
endgrent_r           getprotoent_r           sethostent_r
endhostent_r         getpwent_r              setkey_r_r
endnetent_r          getpwnam_r              setlocale_r
endprotoent_r        getpwuid_r              setnetent_r
endpwent_r           getservbyname_r         setprotoent_r
endservent_r         getservbyport_r         setpwent_r
endusershell_r       getservent_r            setservent_r
endutent_r           getutid-r               setusershell_r
erand48_r            getutent_r              setutent_r
fcvt_r               getusershell_r          srand48_r
fgetgrent_r          getutline_r             strerror_r
fgetpwent_r          gmtime_r                strtoacl_r
getdate_r            inet_ntoa_r             strtoaclpatt_r
getdiskbyname_r      jrand48_r               strtok_r
getgrent_r           l64a_r                  ttyname_r
getgrgid_r           lcong48_r               ultoa_r
getgrnam_r           localtime_r             ultostr_r
gethostbyaddr_r      lrand48_r               utmpname_r
gethostbyname_r      ltoa_r                  wcstok_r
gethostent_r         ltostr_r
getlocale_r          mrand48_r

New, thread-safe routines in libsec are:

endspwent_r
getspwaid_r
getspwaid_r
getspwent-r
getspwnam_r
getspuid_r
setspwent_r

For more information on routines in libsec, refer to "Shadow Password Routines" in the "Compatibility with 9.x Releases" section of the Upgrading from HP-UX 9.x to 10.x manual.

The following routines support locking in threaded applications:

flockfile
funlockfile

flockfile and funlockfile explicitly lock and unlock a FILE object. But a programmer may not need to incur the overhead of locking and unlocking the file on every call.

The programmer can minimize the locking overhead for a series of calls in a threaded application by using the following new routines, which ensure exclusive access to a file for a series of _unlocked stdio calls:

clearerr_unlocked   fseek_unlocked      putwchar_unlocked
fclose_unlocked     ftell_unlocked      putws_unlocked
feof_unlocked       fwrite_unlocked     rewind_unlocked
ferror_unlocked     getc_unlocked       setvbuf_ulocked
fflush_unlocked     getchar_unlocked    ungetc_unlocked
fgets_unlocked      getw_unlocked
fgetwc_unlocked     getwc_unlocked
fgetws_unlocked     getwchar_unlocked
fileno_unlocked     putc_unlocked
fputs_unlocked      putchar_unlocked
fputwc_unlocked     puts_unlocked
fputws_unlocked     putw_unlocked
fread_unlocked      putwc_unlocked

The following routines have slightly different semantics when called from a multi-threaded application using a NULL pointer.

ctermid
cuserid
tmpnam

These routines are called with a pointer to a buffer in which the result is to be stored. For non-threaded applications, providing a NULL pointer indicates that the routine is to store the result in an internal static buffer and return a pointer to that internal buffer. But if a NULL pointer is passed to one of these routines from a multi-threaded application, the operation is not performed and a NULL pointer is returned.

The following routines are not supported for use in threaded applications and have no corresponding thread-safe version.

authdes_getucred        getrpcbyname
authnone_create         getrpcbynumber
bindresvport            getrpcent
callrpc                 gettransient
clnt_create             hcreate
clnt_pcreateerror       hdestroy
clnt_perrno             innetgr
clnt_perror             registerrpc
clnt_spcreateerror      remexportent
clnt_sperrno            setnetgrent
clnt_sperror            setrpcent
endnetgrent             svc_register
endrpcent               svc_unregister
getexportent            xprt_register
getexportopt            xprt_unregister
getnetgrent

10.x closelog conforms to COSE XPG4.2 (SPEC1170); it returns void rather than int.

In the past, when the edflag was non-zero (requesting decryption), encrypt() would return an error. The decrypt capability of the encrypt() function is now available; you no longer need to get a special patch from HP and link in /usr/lib/libcrypt with your applications in order to do decryption.

fnmatch has changed in the following ways:

For 10.0:

Do not mix calls to 9.x glob() and globfree() with calls to their 10.x equivalents; see "Specific Guidelines for Moving Code from 9.x to 10.01" in the "Compatibility with 9.x Releases" section of the Upgrading from HP-UX 9.x to 10.x manual.

10.x nftw passes the constant FTW_SLN to the passed function fn whenever the target is a dangling symbolic link.

In a future release, nftw(3C) may be further changed for COSE XPG4.2 (SPEC1170) compliance, to pass the address of the struct FTW which is passed to the called function fn. The existing prototype,

extern int nftw(const char *path,
    int(*fn)(const char *, const struct stat *, int,
    struct FTW), int depth, int flags);

would become:

extern int nftw(const char *path, int(*fn)
    (const char *, const struct stat *, int, struct FTW *),
    int depth, int flags);

Such a change would require source code changes to application code which calls nftw.

10.x openlog, like closelog, returns void rather than int.

For 10.0:

How This Affects Your Code

For information on setlocale(3C)/iconv(3C) see the Locales section of the README for NLS in 10.01 (online as /usr/lib/nls/README.nls.10.01).

Change:

See also "Pattern-Matching Routines Mixed in Unusual Ways" in the "Compatibility with 9.x Releases" section of the Upgrading from HP-UX 9.x to 10.x manual.