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author | Ulrich Drepper <drepper@redhat.com> | 1998-02-16 17:42:46 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 1998-02-16 17:42:46 +0000 |
commit | 880f421fc30003d1626429e8796d43b91d71cab9 (patch) | |
tree | dd3aff8b9397dd9177ed24a32d4e6fd2f841ebdd /manual | |
parent | f565518e7e393419f99457792971ce71215d02cc (diff) | |
download | glibc-880f421fc30003d1626429e8796d43b91d71cab9.tar.gz glibc-880f421fc30003d1626429e8796d43b91d71cab9.tar.xz glibc-880f421fc30003d1626429e8796d43b91d71cab9.zip |
Update.
1998-02-16 17:33 Ulrich Drepper <drepper@cygnus.com> * elf/rtld.c (dl_main): Recognize --library-path parameter and pass value (or NULL) to _dl_init_paths. * elf/dl-load.c (_dl_init_paths): Change to take one parameter, replacing local variable llp. If llp is NULL examine LD_LIBRARY_PATH environment variable. * elf/link.h: Change prototype for _dl_init_paths. * elf/dl-support.c: Pass NULL in _dl_init_paths call. * localedata/Makefile (distribute): Add test files. 1998-02-17 Andreas Jaeger <aj@arthur.rhein-neckar.de> * localedata/tests/{test1.cm, test2.cm, test3.cm, test4.cm, test1.def, test2.def, test3.def, test4.def}: Simple input files for localedef. Contributed by Yung-Ching Hsiao <yhsiao@cae.wisc.edu>. * localedata/Makefile (tests): Call tst-locale.sh. * localedata/tst-locale.sh: New file, regression tests for some localedef problems. 1998-02-15 Thorsten Kukuk <kukuk@vt.uni-paderborn.de> * nis/nss_nisplus/nisplus-alias.c: Use __stpncpy. * nis/nss_nisplus/nisplus-hosts.c: Make sure buffer is always NUL terminated. * nis/nss_nisplus/nisplus-network.c: Likewise. * nis/nss_nisplus/nisplus-proto.c: Likewise. * nis/nss_nisplus/nisplus-rpc.c: Likewise. * nis/nss_nisplus/nisplus-service.c: Likewise. Add more changes from TI-RPC 2.3 for rpcgen to fix include/C++ bug and support generating thread safe RPC code. * sunrpc/rpc_main.c: Add changes. * sunrpc/rpc_clntout.c: Likewise. * sunrpc/rpc_cout.c: Likewise. * sunrpc/rpc_hout.c: Likewise. * sunrpc/rpc_parse.c: Likewise. * sunrpc/rpc_sample.c: Likewise. * sunrpc/rpc_scan.c: Likewise. * sunrpc/rpc_svcout.c: Likewise. * sunrpc/rpc_util.c: Likewise. * sunrpc/rpc_util.h: Add new structs and prototypes. * sunrpc/proto.h: Remove prototypes for static functions. 1998-02-15 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * locale/programs/ld-messages.c (messages_finish): Don't skip error checking when being quiet. * locale/programs/ld-ctype.c (ctype_finish): Likewise. (set_class_defaults): Likewise. * locale/programs/charmap.c (parse_charmap): Likewise. * locale/programs/ld-collate.c (collate_finish): Likewise. * locale/programs/ld-monetary.c (monetary_finish): Likewise. * locale/programs/ld-time.c (time_finish): Likewise. * locale/programs/locfile.c (write_locale_data): Likewise. * locale/programs/ld-ctype.c (ctype_class_to): Silently ignore unknown characters and empty ranges. * locale/programs/ld-collate.c (collate_order_elem): When processing an ellipsis properly form a linked list in the result table, fix typo when allocating ordering array. [PR libc/419] 1998-02-13 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * elf/Makefile (ld-map): Define. (rtld-ldscript): Define. Change all `$(objpfx)rtld-ldscript' to `$(rtld-ldscript)'. ($(objpfx)ld.so): Combine the two versions of this rule. Depend on $(ld-map). (rtld-link): Combine the two versions of this definition. Fixed to make it work when no symbol versioning is used. 1998-02-16 Ulrich Drepper <drepper@cygnus.com> * Makeconfig (build-program-cmd): Use --library-path parameter to ld.so instead of environment variable. * sunrpc/Makefile (rpcgen-cmd): Don't use -$ parameter. * sunrpc/rpc_main.c: Remove support for -$$ option again. 1998-02-16 Andreas Jaeger <aj@arthur.rhein-neckar.de> * Make-dist: Respect with-cvs setting. * MakeTAGS (all-pot): Likewise. * sysdeps/sparc/sparc32/Makefile: Likewise. * sysdeps/mach/hurd/Makefile: Likewise. * stdlib/Makefile: Likewise. * posix/Makefile: Likewise. * intl/Makefile: Likewise. * po/Makefile (linguas): Likewise
Diffstat (limited to 'manual')
-rw-r--r-- | manual/arith.texi | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/manual/arith.texi b/manual/arith.texi index 21b6380fca..3b060689a9 100644 --- a/manual/arith.texi +++ b/manual/arith.texi @@ -46,6 +46,7 @@ These functions are declared in the header files @file{math.h} and division. * Parsing of Numbers:: Functions for ``reading'' numbers from strings. +* Old-style number conversion:: Low-level number to string conversion. @end menu @node Infinity @@ -1324,3 +1325,169 @@ need not detect overflow and underflow errors. The @code{atof} function is provided mostly for compatibility with existing code; using @code{strtod} is more robust. @end deftypefun + + +@node Old-style number conversion +@subsection Old-style way of converting numbers to strings + +The @w{System V} library provided three functions to convert numbers to +strings which have a unusual and hard-to-be-used semantic. The GNU C +library also provides these functions together with some useful +extensions in the same sense. + +Generally, you should avoid using these functions unless the really fit +into the problem you have to to solve. Otherwise it is almost always +better to use @code{sprinf} since it's greater availability (it is an +@w{ISO C} function). + + +@comment stdlib.h +@comment SVID, Unix98 +@deftypefun {char *} ecvt (double @var{value}, int @var{ndigit}, int *@var{decpt}, int *@var{sign}) +The function @code{ecvt} converts the floating-point number @var{value} +to a string with at most @var{ndigit} decimal digits. If @code{ndigit} +is greater than the accuracy of the @code{double} floating-point type +the implementation can shorten @var{ndigit} to a reasonable value. The +returned string neither contains decimal point nor sign. The high-order +digit of the string is non-zero (unless @var{value} is actually zero) +and the low-order digit is rounded. The variable pointed to by +@var{decpt} gets the position of the decimal character relative to the +start of the string. If @var{value} is negativ, @var{sign} is set to a +non-zero value, otherwise to 0. + +The returned string is statically allocated and overwritten by each call +to @code{ecvt}. + +If @var{value} is zero, it's implementation defined if @var{decpt} is +@code{0} or @code{1}. + +The prototype for this function can be found in @file{stdlib.h}. +@end deftypefun + +As an example @code{ecvt (12.3, 5, &decpt, &sign)} returns @code{"12300"} +and sets @var{decpt} to @code{2} and @var{sign} to @code{0}. + +@comment stdlib.h +@comment SVID, Unix98 +@deftypefun {char *} fcvt (double @var{value}, int @var{ndigit}, int @var{decpt}, int *@var{sign}) +The function @code{fcvt} is similar to @code{ecvt} with the difference +that @var{ndigit} specifies the digits after the decimal point. If +@var{ndigit} is less than zero, @var{value} is rounded to the left of +the decimal point upto the reasonable limit (e.g., @math{123.45} is only +rounded to the third digit before the decimal point, even if +@var{ndigit} is less than @math{-3}). + +The returned string is statically allocated and overwritten by each call +to @code{fcvt}. + +The prototype for this function can be found in @file{stdlib.h}. +@end deftypefun + +@comment stdlib.h +@comment SVID, Unix98 +@deftypefun {char *} gcvt (double @var{value}, int @var{ndigit}, char *@var{buf}) +The @code{gcvt} function also converts @var{value} to a NUL terminated +string but does in a way similar to the @code{%g} format of +@code{printf}. It also does not use a static buffer but instead uses +the user-provided buffer starting at @var{buf}. It is the user's +responsibility to make sure the buffer is long enough to contain the +result. Unlike the @code{ecvt} and @code{fcvt} function @code{gcvt} +includes the sign and the decimal point character (which is determined +according to the current locale) in the result. Therefore there are yet +less reasons to use this function instead of @code{printf}. + +The return value is @var{buf}. + +The prototype for this function can be found in @file{stdlib.h}. +@end deftypefun + + +All these three functions have in common that they use @code{double} +values as the parameters. Calling these functions using @code{long +double} values would mean a loss of precision due to the implicit +rounding. Therefore the GNU C library contains three more functions +with similar semantic which take @code{long double} values. + +@comment stdlib.h +@comment GNU +@deftypefun {char *} qecvt (long double @var{value}, int @var{ndigit}, int *@var{decpt}, int *@var{sign}) +This function is equivalent to the @code{ecvt} function except that it +takes an @code{long double} value for the first parameter. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun + +@comment stdlib.h +@comment GNU +@deftypefun {char *} qfcvt (long double @var{value}, int @var{ndigit}, int @var{decpt}, int *@var{sign}) +This function is equivalent to the @code{fcvt} function except that it +takes an @code{long double} value for the first parameter. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun + +@comment stdlib.h +@comment GNU +@deftypefun {char *} qgcvt (long double @var{value}, int @var{ndigit}, char *@var{buf}) +This function is equivalent to the @code{gcvt} function except that it +takes an @code{long double} value for the first parameter. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun + + +@cindex gcvt_r +As said above the @code{ecvt} and @code{fcvt} function along with their +@code{long double} equivalents have the problem that they return a value +located in a static buffer which is overwritten by the next call of the +function. This limitation is lifted in yet another set of functions +which also are GNU extensions. These reentrant functions can be +recognized by the by the conventional @code{_r} ending. Obviously there +is no need for a @code{gcvt_r} function. + +@comment stdlib.h +@comment GNU +@deftypefun {char *} ecvt_r (double @var{value}, int @var{ndigit}, int *@var{decpt}, int *@var{sign}, char *@var{buf}, size_t @var{len}) +The @code{ecvt_r} function is similar to the @code{ecvt} function except +that it places its result into the user-specified buffer starting at +@var{buf}. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun + +@comment stdlib.h +@comment SVID, Unix98 +@deftypefun {char *} fcvt_r (double @var{value}, int @var{ndigit}, int @var{decpt}, int *@var{sign}, char *@var{buf}, size_t @var{len}) +The @code{fcvt_r} function is similar to the @code{fcvt} function except +that it places its result into the user-specified buffer starting at +@var{buf}. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun + +@comment stdlib.h +@comment GNU +@deftypefun {char *} qecvt_r (long double @var{value}, int @var{ndigit}, int *@var{decpt}, int *@var{sign}, char *@var{buf}, size_t @var{len}) +The @code{qecvt_r} function is similar to the @code{qecvt} function except +that it places its result into the user-specified buffer starting at +@var{buf}. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun + +@comment stdlib.h +@comment GNU +@deftypefun {char *} qfcvt (long double @var{value}, int @var{ndigit}, int @var{decpt}, int *@var{sign}, char *@var{buf}, size_t @var{len}) +The @code{qfcvt_r} function is similar to the @code{qfcvt} function except +that it places its result into the user-specified buffer starting at +@var{buf}. + +This function is a GNU extension. The prototype can be found in +@file{stdlib.h}. +@end deftypefun |