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authorPatrik Nyblom <[email protected]>2010-06-08 09:59:30 +0200
committerPatrik Nyblom <[email protected]>2010-06-23 14:50:10 +0200
commit01749000e1cdd379df0cbaefb5b49c27f2c496e9 (patch)
tree9702f0205261e62dd261ec17beb6b3363c8f424f
parentc1e94fa9a6fe4ae717d35dfbd1b628dc2e06d26a (diff)
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Teach Unix sys_float.c to ignore underflow in list_to_float and return 0.0
OTP-7178
-rw-r--r--erts/emulator/sys/unix/sys_float.c13
-rw-r--r--erts/emulator/test/float_SUITE.erl29
2 files changed, 38 insertions, 4 deletions
diff --git a/erts/emulator/sys/unix/sys_float.c b/erts/emulator/sys/unix/sys_float.c
index c59c99f65e..0a27b4cafb 100644
--- a/erts/emulator/sys/unix/sys_float.c
+++ b/erts/emulator/sys/unix/sys_float.c
@@ -799,8 +799,17 @@ sys_chars_to_double(char* buf, double* fp)
}
#ifdef NO_FPE_SIGNALS
- if (errno == ERANGE && (*fp == 0.0 || *fp == HUGE_VAL || *fp == -HUGE_VAL)) {
- return -1;
+ if (errno == ERANGE) {
+ if (*fp == HUGE_VAL || *fp == -HUGE_VAL) {
+ /* overflow, should give error */
+ return -1;
+ } else if (t == s && *fp == 0.0) {
+ /* This should give 0.0 - OTP-7178 */
+ errno = 0;
+
+ } else if (*fp == 0.0) {
+ return -1;
+ }
}
#endif
return 0;
diff --git a/erts/emulator/test/float_SUITE.erl b/erts/emulator/test/float_SUITE.erl
index 102e472ea6..99e9457985 100644
--- a/erts/emulator/test/float_SUITE.erl
+++ b/erts/emulator/test/float_SUITE.erl
@@ -22,7 +22,10 @@
-include("test_server.hrl").
-export([all/1,init_per_testcase/2,fin_per_testcase/2,
- fpe/1,fp_drv/1,fp_drv_thread/1,denormalized/1,match/1,bad_float_unpack/1]).
+ fpe/1,fp_drv/1,fp_drv_thread/1,denormalized/1,match/1,
+ bad_float_unpack/1]).
+-export([otp_7178/1]).
+
init_per_testcase(Func, Config) when is_atom(Func), is_list(Config) ->
Dog = ?t:timetrap(?t:minutes(3)),
@@ -33,7 +36,29 @@ fin_per_testcase(_Func, Config) ->
?t:timetrap_cancel(Dog).
all(suite) ->
- [fpe,fp_drv,fp_drv_thread,denormalized,match,bad_float_unpack].
+ [fpe,
+ fp_drv,
+ fp_drv_thread,
+ otp_7178,
+ denormalized,
+ match,
+ bad_float_unpack].
+
+%%
+%% OTP-7178, list_to_float on very small numbers should give 0.0
+%% instead of exception, i.e. ignore underflow.
+%%
+otp_7178(suite) ->
+ [];
+otp_7178(doc) ->
+ ["test that list_to_float on very small numbers give 0.0"];
+otp_7178(Config) when is_list(Config) ->
+ ?line X = list_to_float("1.0e-325"),
+ ?line true = (X < 0.00000001) and (X > -0.00000001),
+ ?line Y = list_to_float("1.0e-325325325"),
+ ?line true = (Y < 0.00000001) and (Y > -0.00000001),
+ ?line {'EXIT', {badarg,_}} = (catch list_to_float("1.0e83291083210")),
+ ok.
%% Forces floating point exceptions and tests that subsequent, legal,
%% operations are calculated correctly. Original version by Sebastian