10564b1175
groff 1.23.0 added .MR to its -man macro package. The NEWS file states
that the inclusion of the macro "was prompted by its introduction to
Plan 9 from User Space's troff in August 2020." From d32deab it seems
that the name for Plan 9 from User Space's implementation was suggested
by groff maintainer G. Brandon Robinson.
Not sure if the intention was to make these definitions compatible, but
it would be nice if they were.
Currently, Plan 9 from User Space's .MR expects its second argument to
be parenthesized. groff's .MR does not. This results in extra
parentheses appearing in manual references when viewing Plan 9 from User
Space's manual pages on a system using groff.
179 lines
3.2 KiB
Groff
179 lines
3.2 KiB
Groff
.TH ATOF 3
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.SH NAME
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atof, atoi, atol, atoll, charstod, strtod, strtol, strtoll, strtoul, strtoull \- convert text to numbers
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.PP
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.nf
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.ta \w'\fLdouble 'u
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.B
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double atof(char *nptr)
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.PP
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.B
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int atoi(char *nptr)
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.PP
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.B
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long atol(char *nptr)
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.PP
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.B
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vlong atoll(char *nptr)
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.PP
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.B
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double charstod(int (*f)(void *), void *a)
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.PP
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.B
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double strtod(char *nptr, char **rptr)
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.PP
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.B
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long strtol(char *nptr, char **rptr, int base)
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.PP
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.B
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vlong strtoll(char *nptr, char **rptr, int base)
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.PP
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.B
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ulong strtoul(char *nptr, char **rptr, int base)
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.PP
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.B
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vlong strtoull(char *nptr, char **rptr, int base)
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.fi
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.SH DESCRIPTION
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.IR Atof ,
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.IR atoi ,
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.IR atol ,
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and
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.I atoll
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convert a string pointed to by
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.I nptr
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to floating, integer, long integer, and long long integer
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.RB ( vlong )
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representation respectively.
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The first unrecognized character ends the string.
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Leading C escapes are understood, as in
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.I strtol
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with
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.I base
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zero (described below).
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.PP
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.I Atof
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recognizes an optional string of tabs and spaces,
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then an optional sign, then
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a string of digits optionally containing a decimal
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point, then an optional
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.L e
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or
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.L E
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followed
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by an optionally signed integer.
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.PP
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.I Atoi
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and
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.I atol
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recognize an optional string of tabs and spaces,
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then an optional sign, then a string of
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decimal digits.
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.PP
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.IR Strtod ,
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.IR strtol ,
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.IR strtoll ,
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.IR strtoul ,
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and
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.I strtoull
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behave similarly to
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.I atof
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and
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.I atol
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and, if
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.I rptr
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is not zero, set
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.I *rptr
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to point to the input character
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immediately after the string converted.
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.PP
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.IR Strtol ,
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.IR strtoll ,
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.IR strtoul ,
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and
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.IR strtoull
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interpret the digit string in the specified
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.IR base ,
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from 2 to 36,
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each digit being less than the base.
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Digits with value over 9 are represented by letters,
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a-z or A-Z.
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If
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.I base
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is 0, the input is interpreted as an integral constant in
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the style of C (with no suffixed type indicators):
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numbers are octal if they begin with
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.LR 0 ,
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hexadecimal if they begin with
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.L 0x
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or
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.LR 0X ,
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otherwise decimal.
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.PP
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.I Charstod
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interprets floating point numbers in the manner of
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.IR atof ,
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but gets successive characters by calling
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.BR (*\fIf\fP)(a) .
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The last call to
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.I f
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terminates the scan, so it must have returned a character that
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is not a legal continuation of a number.
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Therefore, it may be necessary to back up the input stream one character
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after calling
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.IR charstod .
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.SH SOURCE
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.B \*9/src/lib9
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.SH SEE ALSO
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.MR fscanf 3
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.SH DIAGNOSTICS
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Zero is returned if the beginning of the input string is not
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interpretable as a number; even in this case,
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.I rptr
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will be updated.
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.br
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These routines set
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.IR errstr .
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.SH BUGS
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.I Atoi
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and
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.I atol
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accept octal and hexadecimal numbers in the style of C,
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contrary to the ANSI specification.
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.PP
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.IR Atof ,
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.IR strtod ,
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.IR strtol ,
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.IR strtoul ,
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.IR strtoll ,
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and
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.IR strtoull
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are not provided:
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they are expected to be provided by the underlying system.
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.PP
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Because they are implemented in the fmt library,
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.I charstod
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and
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.I strtod
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are preprocessor macros defined as
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.I fmtcharstod
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and
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.IR fmtstrtod .
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.PP
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To avoid name conflicts with the underlying system,
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.IR atoi ,
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.IR atol ,
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and
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.I atoll
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are preprocessor macros defined as
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.IR p9atoi ,
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.IR p9atol ,
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and
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.IR p9atoll ;
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see
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.MR intro 3 .
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