aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/sys/win32
diff options
context:
space:
mode:
authorSerge Aleynikov <[email protected]>2013-01-21 15:36:43 +0100
committerBjörn-Egil Dahlberg <[email protected]>2013-01-21 15:36:43 +0100
commitab27e8699ef2a2bafe574158200993f184de3dc2 (patch)
treea4365e182109d25ce049244b220844705b7d2a25 /erts/emulator/sys/win32
parent9f461fbaf0be7aba7c0b8b89be1f0b6f1141b7a5 (diff)
downloadotp-ab27e8699ef2a2bafe574158200993f184de3dc2.tar.gz
otp-ab27e8699ef2a2bafe574158200993f184de3dc2.tar.bz2
otp-ab27e8699ef2a2bafe574158200993f184de3dc2.zip
Text representation of a float formatted using given options.
This BIF solves a problem of float_to_list/1 that doesn't allow specifying the number of digits after the decimal point when formatting floats. float_to_list(Float, Options) -> string() Float = float() Options = [Option] Option = {decimals, Decimals::0..249} | {scientific, Decimals::0..249} | compact Returns a string which corresponds to the text representation of a `Float` formatted using given options. When decimals option is specified the returned value will contain at most `Decimals` number of digits past the decimal point. When `compact` option is provided the trailing zeros at the end of the list are truncated (this option is only meaningful together with the `decimals` option). When `scientific` option is provided, the float will be formatted using scientific notation with `Decimals` digits of precision. If `Options` is `[]` the function behaves like `float_to_list/1`. When using `decimals` option and the number doesn't fit in the static internal buffer of 256 bytes the function throws `badarg`.
Diffstat (limited to 'erts/emulator/sys/win32')
-rw-r--r--erts/emulator/sys/win32/sys_float.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/erts/emulator/sys/win32/sys_float.c b/erts/emulator/sys/win32/sys_float.c
index 09dad89140..960edaa7a5 100644
--- a/erts/emulator/sys/win32/sys_float.c
+++ b/erts/emulator/sys/win32/sys_float.c
@@ -114,15 +114,16 @@ sys_chars_to_double(char *buf, double *fp)
/*
** Convert a double to ascii format 0.dddde[+|-]ddd
-** return number of characters converted
+** return number of characters converted or -1 if error.
*/
int
-sys_double_to_chars(double fp, char *buffer, size_t buffer_size)
+sys_double_to_chars_ext(double fp, char *buffer, size_t buffer_size, size_t decimals)
{
char *s = buffer;
-
- (void) erts_snprintf(buffer, buffer_size, "%.20e", fp);
+
+ if (erts_snprintf(buffer, buffer_size, "%.*e", decimals, fp) >= buffer_size)
+ return -1;
/* Search upto decimal point */
if (*s == '+' || *s == '-') s++;
while (isdigit(*s)) s++;