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authorUlrich Drepper <drepper@redhat.com>1998-02-16 17:42:46 +0000
committerUlrich Drepper <drepper@redhat.com>1998-02-16 17:42:46 +0000
commit880f421fc30003d1626429e8796d43b91d71cab9 (patch)
treedd3aff8b9397dd9177ed24a32d4e6fd2f841ebdd /manual
parentf565518e7e393419f99457792971ce71215d02cc (diff)
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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.texi167
1 files changed, 167 insertions, 0 deletions
diff --git a/manual/arith.texi b/manual/arith.texi
index 21b6380..3b06068 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