Several programmers have been confused about this use of 'deprecated'. Also, maximum field width can be used with these fields to mitigate the problem. Still, it's only a mitigation, since it limits the number of characters read, but that means an input of LONG_MAX+1 --which takes up the same number of characters than LONG_MAX-- would still cause UB; or one can limit that to well below the limit of UB, but then you artificially invalidate valid input. No good way to avoid UB with sscanf(3), but it's not necessarily bad with trusted input (and strtol(3) isn't the panacea either; strtoi(3) is good, though, but not standard). Try to be more convincing in BUGS instead. Link: <https://stackoverflow.com/questions/77601832/man-sscanf-d-is-deprecated-in-c-or-glibc/> Cc: Lee Griffiths <poddster@xxxxxxxxx> Cc: Zack Weinberg <zack@xxxxxxxxxxxx> Signed-off-by: Alejandro Colomar <alx@xxxxxxxxxx> --- Hi Lee! Thanks for the report. After seeing how much frustration it has caused, I propose this change. Does it look good to you? Thanks, Alex man3/sscanf.3 | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) diff --git a/man3/sscanf.3 b/man3/sscanf.3 index 2211cab7d..4c0bdc318 100644 --- a/man3/sscanf.3 +++ b/man3/sscanf.3 @@ -359,7 +359,6 @@ .SS Conversions and assignment does not occur. .TP .B d -.IR Deprecated . Matches an optionally signed decimal integer; the next pointer must be a pointer to .IR int . @@ -374,7 +373,6 @@ .SS Conversions .\" is silently ignored, causing old programs to fail mysteriously.) .TP .B i -.IR Deprecated . Matches an optionally signed integer; the next pointer must be a pointer to .IR int . The integer is read in base 16 if it begins with @@ -387,18 +385,15 @@ .SS Conversions Only characters that correspond to the base are used. .TP .B o -.IR Deprecated . Matches an unsigned octal integer; the next pointer must be a pointer to .IR "unsigned int" . .TP .B u -.IR Deprecated . Matches an unsigned decimal integer; the next pointer must be a pointer to .IR "unsigned int" . .TP .B x -.IR Deprecated . Matches an unsigned hexadecimal integer (that may optionally begin with a prefix of .I 0x @@ -409,33 +404,27 @@ .SS Conversions .IR "unsigned int" . .TP .B X -.IR Deprecated . Equivalent to .BR x . .TP .B f -.IR Deprecated . Matches an optionally signed floating-point number; the next pointer must be a pointer to .IR float . .TP .B e -.IR Deprecated . Equivalent to .BR f . .TP .B g -.IR Deprecated . Equivalent to .BR f . .TP .B E -.IR Deprecated . Equivalent to .BR f . .TP .B a -.IR Deprecated . (C99) Equivalent to .BR f . .TP @@ -661,8 +650,8 @@ .SS Numeric conversion specifiers programs should use functions such as .BR strtol (3) to parse numeric input. -This manual page deprecates use of the numeric conversion specifiers -until they are fixed by ISO C. +Alternatively, +mitigate it by specifying a maximum field width. .SS Nonstandard modifiers These functions are fully C99 conformant, but provide the additional modifiers -- 2.42.0
Attachment:
signature.asc
Description: PGP signature
